Side effects of pristiq



The following adverse reactions are discussed in greater detail in other sections of the label.

  • Hypersensitivity
  • Suicidal Thoughts and Behaviors in Adolescents and Young Adults
  • Serotonin Syndrome
  • Elevated Blood Pressure
  • Abnormal Bleeding
  • Angle Closure Glaucoma
  • Activation of Mania/Hypomania
  • Discontinuation Syndrome
  • Seizure
  • Hyponatremia
  • Interstitial Lung Disease and Eosinophilic Pneumonia

Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice.

Patient Exposure

PRISTIQ was evaluated for safety in 8,394 patients diagnosed with major depressive disorder who participated in multiple-dose pre-marketing studies, representing 2,784 patient-years of exposure. Of the total 8,394 patients exposed to at least one dose of PRISTIQ; 2,116 were exposed to PRISTIQ for 6 months, representing 1,658 patient-years of exposure, and 421 were exposed for one year, representing 416 patient-years of exposure.

Adverse Reactions Reported As Reasons For Discontinuation Of Treatment

In the pre-marketing pooled 8-week placebo-controlled studies in patients with MDD, 1,834 patients were exposed to PRISTIQ (50 to 400 mg). Of the 1,834 patients, 12% discontinued treatment due to an adverse reaction, compared with 3% of the 1,116 placebo-treated patients. At the recommended dose of 50 mg, the discontinuation rate due to an adverse reaction for PRISTIQ (4.1%) was similar to the rate for placebo (3.8%). For the 100 mg dose of PRISTIQ the discontinuation rate due to an adverse reaction was 8.7%.

The most common adverse reactions leading to discontinuation in at least 2% and at a rate greater than placebo of the PRISTIQ treated patients in the short-term studies, up to 8 weeks, were: nausea (4%); dizziness, headache and vomiting (2% each). In a longer-term study, up to 9 months, the most common was vomiting (2%).

Common Adverse Reactions In Placebo-Controlled MDD Studies

The most commonly observed adverse reactions in PRISTIQ treated MDD patients in premarketing pooled 8-week, placebo-controlled, fixed-dose studies (incidence ≥ 5% and at least twice the rate of placebo in the 50 or 100 mg dose groups) were: nausea, dizziness, insomnia, hyperhidrosis, constipation, somnolence, decreased appetite, anxiety, and specific male sexual function disorders.

Table 2 shows the incidence of common adverse reactions that occurred in ≥ 2% of PRISTIQ treated MDD patients and twice the rate of placebo at any dose in the pre-marketing pooled 8week, placebo-controlled, fixed dose clinical studies

Table 2: Common Adverse Reactions (≥ 2% in any Fixed-Dose Group and Twice the Rate of Placebo) in Pre-marketing Pooled MDD 8-Week Placebo-Controlled Studies

Percentage of Patients Reporting Reaction
System Organ Class Preferred Term Placebo
50 mg
100 mg
200 mg
400 mg
Cardiac disorders
Blood pressure increased 1 1 1 2 2
Gastrointestinal disorders
Nausea 10 22 26 36 41
Dry mouth 9 11 17 21 25
Constipation 4 9 9 10 14
Vomiting 3 3 4 6 9
General disorders and administration site conditions
Fatigue 4 7 7 10 11
Chills 1 1 <1 3 4
Feeling jittery 1 1 2 3 3
Metabolism and nutrition disorders
Decreased appetite 2 5 8 10 10
Nervous system disorders
Dizziness 5 13 10 15 16
Somnolence 4 4 9 12 12
Tremor 2 2 3 9 9
Disturbance in attention <1 <1 1 2 1
Psychiatric disorders
Insomnia 6 9 12 14 15
Anxiety 2 3 5 4 4
Nervousness 1 <1 1 2 2
Abnormal dreams 1 2 3 2 4
Renal and urinary disorders
Urinary hesitation 0 <1 1 2 2
Respiratory, thoracic and mediastinal disorders
Yawning <1 1 1 4 3
Skin and subcutaneous tissue disorders
Hyperhidrosis 4 10 11 18 21
Special Senses
Vision blurred 1 3 4 4 4
Mydriasis <1 2 2 6 6
Vertigo 1 2 1 5 3
Tinnitus 1 2 1 1 2
Dysgeusia 1 1 1 1 2
Vascular disorders
Hot flush <1 1 1 2 2

Sexual Function Adverse Reactions

Table 3 shows the incidence of sexual function adverse reactions that occurred in ≥ 2% of PRISTIQ treated MDD patients in any fixed-dose group (pre-marketing pooled 8-week, placebo-controlled, fixed -dose, clinical studies).

Table 3: Sexual Function Adverse Reactions (≥ 2% in Men or Women in any PRISTIQ Group) During the On-Therapy Period

50 mg
100 mg
200 mg
400 mg
Men only
Anorgasmia 0 0 3 5 8
Libido decreased 1 4 5 6 3
Orgasm abnormal 0 0 1 2 3
Ejaculation delayed <1 1 5 7 6
Erectile dysfunction 1 3 6 8 11
Ejaculation disorder 0 0 1 2 5
Ejaculation failure 0 1 0 2 2
Sexual dysfunction 0 1 0 0 2
50 mg
100 mg
200 mg
400 mg
Women only
Anorgasmia 0 1 1 0 3

Other Adverse Reactions Observed In Premarketing And Postmarketing Clinical Studies

Other infrequent adverse reactions, not described elsewhere in the label, occurring at an incidence of < 2% in MDD patients treated with PRISTIQ were:

Cardiac disorders – Tachycardia.

General disorders and administration site conditions – Asthenia.

Investigations – Weight increased, liver function test abnormal, blood prolactin increased.

Musculoskeletal and connective tissue disorders – Musculoskeletal stiffness.

Nervous system disorders -Syncope, convulsion, dystonia.

Psychiatric disorders – Depersonalization, bruxism.

Renal and urinary disorders – Urinary retention.

Skin and subcutaneous tissue disorders – Rash, alopecia, photosensitivity reaction, angioedema.

In clinical studies, there were uncommon reports of ischemic cardiac adverse reactions, including myocardial ischemia, myocardial infarction, and coronary occlusion requiring revascularization; these patients had multiple underlying cardiac risk factors. More patients experienced these events during PRISTIQ treatment as compared to placebo.

Laboratory, ECG And Vital Sign Changes Observed In MDD Clinical Studies

The following changes were observed in pre-marketing placebo-controlled, short-term MDD studies with PRISTIQ.


Elevations in fasting serum total cholesterol, LDL (low density lipoproteins) cholesterol, and triglycerides occurred in the controlled studies. Some of these abnormalities were considered potentially clinically significant.

The percentage of patients who exceeded a predetermined threshold value is shown in Table 4.

Table 4: Incidence (%) of Patients With Lipid Abnormalities of Potential Clinical Significance*

50 mg 100 mg 200mg 400 mg
Total Cholesterol *(Increase of ≥ 50 mg/dl and an absolute value of ≥ 261 mg/dl) 2 3 4 4 10
LDL Cholesterol *(Increase ≥ 50 mg/dl and an absolute value of ≥ 190 mg/dl) 0 1 0 1 2
Triglycerides, fasting *(Fasting: ≥ 327 mg/dl) 3 2 1 4 6


Proteinuria, greater than or equal to trace, was observed in the pre-marketing fixed-dose controlled studies (see Table 5). This proteinuria was not associated with increases in BUN or creatinine and was generally transient.

Table 5: Incidence (%) of Patients with Proteinuria in the Fixed-dose Clinical Studies

Treatment Group Proportion of Patients with Sustained Hypertension
Placebo 0.5%
PRISTIQ 50 mg per day 1.3%
PRISTIQ 100 mg per day 0.7%
PRISTIQ 200 mg per day 1.1%
PRISTIQ 400 mg per day 2.3%

Vital Sign Changes

Table 6 summarizes the changes that were observed in placebo-controlled, short-term, pre-marketing studies with PRISTIQ in patients with MDD (doses 50 to 400 mg).

Table 6: Mean Changes in Vital Signs at Final on Therapy for All Short-term, Fixed-dose Controlled Studies

Treatment with PRISTIQ at all doses from 50 mg per day to 400 mg per day in controlled studies was associated with sustained hypertension, defined as treatment-emergent supine diastolic blood pressure (SDBP) ≥90 mm Hg and ≥10 mm Hg above baseline for 3 consecutive on-therapy visits (see Table 7). Analyses of patients in PRISTIQ pre-marketing short-term controlled studies who met criteria for sustained hypertension revealed a consistent increase in the proportion of patients who developed sustained hypertension. This was seen at all doses with a suggestion of a higher rate at 400 mg per day.

Table 7: Proportion of Patients with Sustained Elevation of Supine Diastolic Blood Pressure

Treatment Group Proportion of Patients with Sustained Hypertension
Placebo 0.5%
PRISTIQ 50 mg per day 1.3%
PRISTIQ 100 mg per day 0.7%
PRISTIQ 200 mg per day 1.1%
PRISTIQ 400 mg per day 2.3%

Orthostatic Hypotension

Postmarketing Experience

The following adverse reaction has been identified during post-approval use of PRISTIQ. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:

Skin and subcutaneous tissue disorders – Stevens-Johnson syndrome.

Gastrointestinal disorders – Pancreatitis acute.

Cardiovascular system – Takotsubo cardiomyopathy.

Read the entire FDA prescribing information for Pristiq (Desvenlafaxine Extended-Release Tablets)


Before taking desvenlafaxine,

  • tell your doctor and pharmacist if you are allergic to desvenlafaxine, venlafaxine (Effexor), any other medications, or any of the ingredients in desvenlafaxine tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
  • tell your doctor if you are taking a monoamine oxidase (MAO) inhibitor, such as isocarboxazid (Marplan), linezolid (Zyvox), methylene blue, phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate), or if you have stopped taking one of these medications within the past 14 days. Your doctor will probably tell you that you should not take desvenlafaxine. If you stop taking desvenlafaxine, your doctor will tell you that you should wait at least 7 days before you start to take an MAO inhibitor.
  • you should know that desvenlafaxine is very similar to another SNRI, venlafaxine (Effexor). You should not take these medications together.
  • tell your doctor and pharmacist what other prescription and nonprescription medications or vitamins you are taking or plan to take. Be sure to mention any of the following: amphetamines such as amphetamine (in Adderall), dextroamphetamine (Dexedrine, Dextrostat, in Adderall), and methamphetamine (Desoxyn); anticoagulants (‘blood thinners’) such as warfarin (Coumadin); certain antifungals such as itraconazole (Sporanox) and ketoconazole (Nizoral); amiodarone (Cordarone, Pacerone); aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn); atomoxetine (Straterra); buspirone (Buspar); clarithromycin (Biaxin); dextromethorphan (found in many cough medications; in Nuedexta); diuretics (‘water pills’); fentanyl (Actiq, Duragesic, Fentora); lithium (Eskalith, Lithobid); medications for anxiety, mental illness, or seizures; certain medications for human immunodeficiency virus (HIV) such as indinavir (Crixivan), nelfinavir (Viracept), and ritonavir (Norvir); medications for migraine such as almotriptan (Axert), eletriptan (Relpax), frovatriptan (Frova), naratriptan (Amerge), rizatriptan (Maxalt), sumatriptan (Imitrex), and zolmitriptan (Zomig); metoprolol (Lopressor, Toprol XL); midazolam; nebivolol (Bystolic); nefazodone; perphenazine (in Duo-Vil); sedatives; selective serotonin reuptake inhibitors (SSRIs) such as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), paroxetine (Paxil), and sertraline (Zoloft); other SNRIs such as duloxetine (Cymbalta); sibutramine (Meridia); sleeping pills; tolterodine (Detrol); tramadol (Ultram); tranquilizers; and tricyclic antidepressants such as amitriptyline, amoxapine (Asendin), clomipramine (Anafranil), desipramine (Norpramin), doxepin (Sinequan), imipramine (Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with desvenlafaxine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • tell your doctor what herbal products and nutritional supplements you are taking, especially St. John’s wort and tryptophan.
  • tell your doctor if you use or have ever used street drugs or have ever overused prescription medications. Also tell your doctor if you have recently had a heart attack and if you have or have ever had: bleeding problems; a stroke; high blood pressure; high cholesterol or triglycerides (fats in the blood);seizures; low sodium levels in the blood; or heart, kidney, or liver disease.
  • tell your doctor if you are pregnant, especially if you are in the last few months of your pregnancy, or if you plan to become pregnant or are breast-feeding. If you become pregnant while taking desvenlafaxine, call your doctor. Desvenlafaxine may cause problems in newborns following delivery if it is taken during the last months of pregnancy.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking desvenlafaxine.
  • you should know that desvenlafaxine may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
  • ask your doctor about the safe use of alcoholic beverages while you are taking desvenlafaxine. Alcohol can make the side effects from desvenlafaxine worse.
  • you should know that in older adults, desvenlafaxine may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.
  • you should know that desvenlafaxine may cause angle-closure glaucoma (a condition where the fluid is suddenly blocked and unable to flow out of the eye causing a quick, severe increase in eye pressure which may lead to a loss of vision). Talk to your doctor about having an eye examination before you start taking this medication. If you have nausea, eye pain, changes in vision, such as seeing colored rings around lights, and swelling or redness in or around the eye, call your doctor or get emergency medical treatment right away.

If you have moderate to severe depression that affects your daily life, you and your doctor may discuss treatment: usually a combination of antidepressants and a referral to a therapist. In research, antidepressant medications have been found to be similar when it comes to safety and how well they work. Still, my patients tend to bring up similar concerns about using them—and you might, too. Let’s look at 10 of the most common myths and misconceptions about antidepressants here.

1) My depression can go away on its own

Some people think, “Maybe I should just ride it out and not take any medication at all.”

Depression tends to get worse the longer it isn’t treated, and untreated depression can lead to a number of other problems, including weight gain, physical pain and illness, alcohol and drug use, relationship difficulties, and suicidal thoughts or attempts.

Additionally, the longer you have untreated depression, the harder it is to achieve full recovery.

2) Antidepressants don’t work

In many folks, they do work. Studies show that anywhere between 40% to 60% of people who take antidepressants see their symptoms improve within 6 to 8 weeks.

Are there differences in how well they work? Not major ones, according to research. For example, selective serotonin reuptake inhibitor antidepressants (SSRIs) like sertraline (Zoloft) and fluoxetine (Prozac) are just as effective for depression as SNRI antidepressants like duloxetine (Cymbalta) and venlafaxine (Effexor).

In controlled research environments, small differences have been observed. Studies seem to show that some of the most effective antidepressants are amitriptyline (Elavil), mirtazapine (Remeron), duloxetine, venlafaxine, and paroxetine (Paxil). Trazodone, fluoxetine, and bupropion (Wellbutrin) may be less effective.

But again, the differences in how well they work are very small. Which one you choose will likely depend on other factors, like if you experience side effects or are taking other medications.

3) Antidepressants have horrible side effects

Antidepressants do cause side effects, but these effects will vary depending on the person, dose, and type of antidepressant.

As a whole, SSRIs such as escitalopram (Lexapro) and fluoxetine (Prozac) reportedly cause the fewest side effects, while tricyclic antidepressants (TCAs) such as imipramine (Tofranil) and nortriptyline (Pamelor) and monoamine oxidase inhibitors (MAOIs) such as tranylcypromine (Parnate) and phenelzine (Nardil) tend to cause more side effects. It’s worth discussing with your doctor if you have concerns.

Antidepressant side effects often go away after a few weeks, but your doctor may adjust your dosing or recommend a different treatment regimen if needed.

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4) Antidepressants will make me gain weight

How an antidepressant affects weight depends on the specific drug, and it can also vary from person to person.

In general, most SSRI antidepressants do not cause weight gain. Paroxetine is the only SSRI that might be associated with weight gain, while the others tend to have no effect on weight. Mirtazapine is also a culprit in weight gain. On the flipside, bupropion SR and bupropion XL might actually cause weight loss.

5) I won’t be able to sleep if I take antidepressants

This is a valid concern if you experience insomnia. First, insomnia can be a symptom of depression, so treating your depression might resolve your insomnia. Second, know that different antidepressants have different effects on sleep.

The antidepressants that may lead to trouble sleeping are paroxetine, sertraline, and bupropion.

On the other hand, folks struggling with sleep might want to take advantage of antidepressants with drowsy side effects like amitriptyline, trazodone, and mirtazapine, which may counteract insomnia.

6) If I choose to stop taking antidepressants, I’ll have horrible withdrawal symptoms

Antidepressant withdrawal is possible if you abruptly stop taking an antidepressant. You’re more likely to have withdrawal symptoms if you’ve been taking the antidepressant for at least 6 weeks.

Certain antidepressants are more likely to cause withdrawal symptoms than others. In general, medications that leave your system faster, such as paroxetine, are more likely to cause withdrawal symptoms than those that stay in your system longer, such as fluoxetine.

Symptoms are similar for SSRI and TCA antidepressants and include headache, tiredness, nausea, appetite problems, insomnia, dizziness, and anxiety. Symptoms for MAOIs tend to be more serious and include trouble thinking clearly, agitation, delusions, and hallucinations.

Weaning your dose down over 1 to 3 weeks is the best way to minimize side effects and help prevent withdrawal. Work with your provider on the best dose/schedule.

7) Antidepressants cause sexual side effects

Several types of antidepressants do have sexual side effects, particularly the SSRIs, SNRIs, TCAs, and MAOIs. Effects include lower sexual desire, delayed orgasm, and erection and ejaculation problems.

Bupropion, for example, has very little effect on sexual function and is a good alternative if you are having sexual side effects with another antidepressant. Of the SSRIs, the risk of sexual dysfunction is highest with paroxetine and lowest with fluoxetine and sertraline.

Also, it’s important to find out if your sexual problems are a symptom of your depression, or if they’re actually due to a medication side effect.

8) Antidepressants will make my headaches worse

Not true. Headaches are not commonly reported with antidepressants. In fact, some may even help with headaches. If you have chronic, tension-type headaches, amitriptyline taken at night has been shown to help prevent them. Mirtazapine and venlafaxine are second-line choices that may also help prevent tension-type headaches.

9) Antidepressants will make me sick to my stomach

Most antidepressants do not cause an upset stomach once you and your provider have settled on a fixed dosage. SSRIs cause higher rates of nausea than bupropion and mirtazapine, and rates between SSRIs and trazodone and duloxetine are about the same. Venlafaxine is known for causing nausea more often than SSRIs.

10) Antidepressants are expensive

Also not true. Just stay away from newer, brand-name antidepressants because the rest are significantly cheaper. Viibryd and Trintellix are brand-name antidepressants that cost a lot more than generic SSRIs, but they haven’t been found to be much better in terms of treating depression. The only side note is that researchers are looking into whether Trintellix might have an added benefit. In a study from 2018, Trintellix significantly improved cognition (thinking and understanding) among study subjects. Interesting.

Hope this helps.

– – –

Dr O.

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  • Why Pristiq

    By participating in the PRISTIQ Savings Offer Program, you acknowledge that you currently meet the eligibility criteria and will comply with the terms and conditions described below:

    • Patients are not eligible to use this Savings Offer if they are enrolled in a state or federally funded insurance program, including but not limited to Medicaid, Medicare, TRICARE, Veterans Affairs health care, a state prescription drug assistance program, or the Government Health Insurance Plan available in Puerto Rico (formerly known as “La Reforma de Salud”)
    • Patient must have private insurance. Offer is not valid for cash-paying patients. The value of this Savings Offer is limited to $90 per use or the amount of your co-pay, whichever is less
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    • For help with the PRISTIQ Savings Offer, call 1-800-725-4125 or write: PRISTIQ Savings Offer, 2250 Perimeter Park Drive, Suite 300, Morrisville, NC 27560

    If your pharmacy does not participate, you may be able to submit a request for a rebate in connection with this Savings Offer. Pay for your PRISTIQ prescription and mail copy of original pharmacy receipt (cash register receipt NOT valid) with product name, date, and amount circled to:

    PRISTIQ Savings Offer, 2250 Perimeter Park Drive, Suite 300, Morrisville, NC 27560

    Be sure to include a copy of the front of your PRISTIQ savings card, your name, and mailing address. Please expect up to 4 to 6 weeks for reimbursement.

    PRISTIQ is available by prescription only.

    Patients should always ask their doctors for medical advice about adverse events.

    The health information contained in this site is provided for educational purposes only and is not intended to replace discussions with a healthcare provider. All decisions regarding patient care must be made with a healthcare provider, considering the unique characteristics of the patient.

    The product information provided in this site is intended only for residents of the United States. The products discussed in this site may have different product labeling in different countries.


    Desvenlafaxine (DV) succinate (Pristiq; Wyeth) is a recent serotonin-norepinephrine reuptake-inhibiting (SNRI) antidepressant drug. DV is O-desmethylvenlafaxine, the principal active metabolite of venlafaxine, formed by the action of CYP 2D6 on the parent drug. In February 2008, DV (50 mg/day) was approved for the treatment of depression by the Food and Drug Administration (FDA) in the USA.

    If patients receive venlafaxine, DV is formed in their bodies; so, what is gained if venlafaxine is eliminated from the treatment chain and DV is administered directly? A cynical answer is that DV extends the patent life of venlafaxine. Whereas venlafaxine went out of patent in 2008, the extended-release formulation of the drug will go out of patent in 2010. In India, unless a substantial advantage for DV over venlafaxine is demonstrated, the introduction of DV will be considered to be evergreening; i.e., merely an incremental modification of an existing molecule. Evergreening is not recognized for the grant of patents under the Indian Patents Act as modified by the Parliament in 2005.

    Therefore, does DV have any advantages over venlafaxine? At present, it is too early to say. There are both positives and negatives for DV. Positives for DV over venlafaxine are:

    1. In clinical trials of patients with major depressive disorder, assessments using a visual analogue scale showed that DV (100-400 mg/day) has a greater efficacy than placebo against painful symptoms associated with depression.

    2. In clinical trials of patients with major depressive disorder, assessments using the Sheehan Disability Scale showed that DV (50-400 mg/day) has a greater efficacy than placebo against disability associated with depression.

    3. DV has demonstrated efficacy against the vasomotor symptoms (hot flushes) of menopause.

    It is likely, however, that these properties of DV constitute a class action of all antidepressants and are not unique to DV. More specific advantages with DV over venlfaxine are:

    1. In order to maximize tolerance, clinicians usually take 7-10 days or longer to uptitrate the dose of venlafaxine to the target of 150-225 mg/day, at which doses venlafaxine becomes dual-acting. In contrast, DV is started at the target dose of 50 mg/day from the very first day. Should it be considered necessary, an escalation to 100 mg/day can be effected within 4-7 days.

    2. CYP 2D6 poor metabolizers constitute about 10% of the population. Such persons would not tolerate standard doses of venlafaxine. Unless clinicians order blood levels or pharmacogenomic tests, they will have no way of knowing whether a patient who develops adverse effects with venlafaxine is a poor metabolizer (in whom lower doses would achieve effective blood levels with fewer adverse effects) or merely does not tolerate standard doses of the drug (necessitating drug withdrawal). Venlafaxine will therefore (unnecessarily) be withdrawn in the former subgroup. In contrast, DV is negligibly metabolized in the liver. Therefore, genetic variations in metabolic capacity will not influence the tolerability of the drug or influence adverse effect-related drug withdrawal decisions.

    3. Venlafaxine is associated with an up to 10% or greater dose-dependent risk of treatment-emergent hypertension. In contrast, in patients who receive DV (50-400 mg/day), there is only an approximately 1-2% risk of sustained increase in diastolic blood pressure to values >90 mmHg or values >10 mmHg above baseline (as compared with a 0.5% risk in patients receiving placebo).

    4. Sexual adverse effects are common with venlafaxine. In contrast, sexual adverse effects are placebo-level with DV 50-100 mg/day, rising to noticeably above placebo level (more in men than in women) only with the 400 mg/day dose. A caveat here is that sexual adverse effects with DV were recorded based on spontaneous reports and had not been formally evaluated in the clinical trials available so far, and could therefore be underestimated.

    5. Venlafaxine is commonly associated with an unpleasant drug discontinuation reaction because its (terminal) half-life is short – about 5 h. This half-life does not vary as a function of immediate-release vs. extended-release formulation. As a result, the drug is substantially washed out of the body 24 h after a single missed dose. This is why discontinuation symptoms may emerge after even a single missed dose of venlafaxine, and why venlafaxine is best dosed at the same time of day each day. Whereas DV is also associated with a discontinuation syndrome, from a theoretical perspective, because its terminal half-life is longer at around 10 h, a drug discontinuation reaction could be less of a problem as compared with venlafaxine. A caveat here is that, as one molecule of venlafaxine yields one molecule of DV upon metabolism, this putative advantage assumes that venlafaxine and DV have subtle pharmacodynamic differences, and that DV does not compensate pharmacodynamically for the hiatus arising from the washout of venlafaxine. The issue can only be resolved through a head-to-head comparison of discontinuation symptoms between the two drugs; these data have so far not been released.

    The above notwithstanding, there are some concerns about DV and some regards in which it has yet to establish itself relative to venlafaxine:

    1. Many doses of DV in many trials failed to separate from placebo for the primary outcome measure. This failure was more marked in the flexible-dose (200-400 mg/day) studies and with the 200 mg/day dose in the fixed-dose studies; however, failure at the primary outcome measure was also recorded with the 50 and 100 mg/day doses in certain fixed-dose studies. Clearcut separation for all outcome measures with all doses in all studies, and in both fixed- and flexible-dose designs, emerged only in pooled analyses. However, effect sizes remained low (around 0.30 or less) and onset of separation from placebo was late (2-4 weeks).

    2. Data exist to suggest that venlafaxine is associated with better treatment outcomes than the selective serotonin reuptake inhibitors (SSRIs), and that venlafaxine may benefit patients who fail SSRI trials. No such studies have so far been conducted with DV.

    DV is about 11 times more potent an inhibitor of serotonin reuptake than of norepinephrine reuptake. Just as venlafaxine becomes a dual-acting SNRI drug only at higher doses (e.g., 150 mg/day and above), might it be possible that DV is merely an SSRI at lower doses? If so, this might, at least in part, explain some of the disappointing results with the drug in the clinical trials conducted to date. Such a possibility is supported by the adverse effect profile of the drug in 50-100 mg/day doses: nausea and dizziness, which are serotonergic adverse effects, are noticeably present whereas dysuria and hypertension, which are noradrenergic adverse effects, are negligible or absent.

    Here, it may be noted that strongly noradrenergic drugs such as reboxetine and more balanced SNRIs such as duloxetine and milnacipran have both found poor acceptance in clinical practice and/or have evidenced unimpressive results relative to SSRIs in meta-analyses. If DV is more strongly noradrenergic than venlafaxine, this may explain the somewhat unimpressive clinical trial results. However, as noted above, the adverse effect profile of the drug does not seem to suggest a noradrenergic bias.

    With this background, mark True or False against each of the following statements:

    1. The dose-dependent risk of dry mouth and constipation with DV is due to muscarinic receptor blockade.

    2. Patients prescribed DV may lose weight.

    3. DV results in a clinically significant increase in the QTc interval.

    4. DV inhibits CYP 2D6.

    5. DV should be avoided in patients with liver disease.

    6. DV should be avoided in patients with renal disease.

    7. DV separates from placebo by week 1 in menopausal women with hot flushes.

    8. The 100 mg/day dose of DV optimizes safety and adverse effects in the treatment of the vasomotor symptoms of menopause.

    PRISTIQ (desvenlafaxine succinate)

    Warnings And Precautions


    Pediatrics: Placebo-Controlled Clinical Trial Data

    Recent analyses of placebo-controlled clinical trial safety databases from Selective Serotonin Reuptake Inhibitors (SSRIs) and other newer anti-depressants suggest that use of these drugs in patients under the age of 18 may be associated with behavioural and emotional changes, including an increased risk of suicidal ideation and behaviour over that of placebo.

    The small denominators in the clinical trial database, as well as the variability in placebo rates, preclude reliable conclusions on the relative safety profiles among the drugs in the class.

    Adults and Pediatrics: Additional data

    There are clinical trial and post-marketing reports with SSRIs and other newer antidepressants, in both pediatrics and adults, of severe agitation-type adverse events coupled with self-harm or harm to others. The agitation-type events include: akathisia, agitation, disinhibition, emotional lability, hostility, aggression, depersonalization. In some cases, the events occurred within several weeks of starting treatment. Rigorous clinical monitoring for suicidal ideation or other indicators of potential for suicidal behaviour is advised in patients of all ages especially when initiating therapy or during any change in dose or dosage regimen. This includes monitoring for agitation-type emotional and behavioural changes.

    An FDA meta-analysis of placebo-controlled clinical trials of antidepressant drugs in adult patients ages 18 to 24 years with psychiatric disorders showed an increased risk of suicidal behaviour with antidepressants compared to placebo.


    Aggression may occur in some patients who have received antidepressants, including desvenlafaxine treatment, dose reduction, or discontinuation. As with other antidepressants, desvenlafaxine should be used cautiously in patients with a history of aggression.


    Discontinuation effects are well known to occur with antidepressants, and sometimes these effects can be protracted and severe (see ADVERSE REACTIONS). Suicide/suicidal thoughts and aggression have been observed in patients during changes in desvenlafaxine dosing regimen, including during discontinuation (see WARNINGS AND PRECAUTIONS, Discontinuation Effects). It is therefore recommended that the dosage of desvenlafaxine be tapered gradually and individually and the patients be closely monitored during discontinuation (see DOSAGE AND ADMINISTRATION). In some patients, discontinuation could take months or longer.

    Sexual Dysfunction

    Serotonin-norepinephrine reuptake inhibitors (SNRIs) may cause symptoms of sexual dysfunction (see ADVERSE REACTIONS). There have been reports of long-lasting sexual dysfunction where the symptoms have continued despite discontinuation of SNRIs.


    Concomitant Use of PRISTIQ with VENLAFAXINE

    Since desvenlafaxine is the major active metabolite of venlafaxine, concomitant use of PRISTIQ with products containing Venlafaxine is not recommended since the combination of the two will lead to additive desvenlafaxine exposure.

    Allergic Reactions

    Patients should be advised to notify their physician if they develop a rash, hives or a related allergic phenomenon.

    Bone Fracture Risk

    Epidemiological studies show an increased risk of bone fractures following exposure to some antidepressants, including SSRIs/SNRIs. The risks appear to be greater at the initial stages of treatment, but significant increased risks were also observed at later stages of treatment. The possibility of fracture should be considered in the care of patients treated with PRISTIQ. Elderly patients and patients with important risk factors for bone fractures should be advised of possible adverse events which increase the risk of falls, such as dizziness and orthostatic hypotension, especially at the early stages of treatment but also soon after withdrawal. Preliminary data from observational studies show association of SSRIs/SNRIs and low bone mineral density in older men and women. Until further information becomes available, a possible effect on bone mineral density with long term treatment with SSRIs/SNRIs, including PRISTIQ, cannot be excluded, and may be a potential concern for patients with osteoporosis or major risk factors for bone fractures.

    Carcinogenesis and Mutagenesis

    For animal data see TOXICOLOGY.


    Caution is advised in administering PRISTIQ to patients with cardiovascular, cerebrovascular, or lipid metabolism disorders (see Clinical Trial Adverse Drug Reactions). Increases in blood pressure and heart rate were observed in clinical trials with PRISTIQ. PRISTIQ has not been evaluated systematically in patients with a recent history of myocardial infarction, unstable heart disease, uncontrolled hypertension, or cerebrovascular disease. Patients with these diagnoses, except for cerebrovascular disease, were excluded from clinical trials.

    Effects on blood pressure
    Cases of elevated blood pressure requiring immediate treatment have been reported with desvenlafaxine in postmarketing experience, including reports of hypertensive crisis and malignant hypertension. Increases in blood pressure were observed in some patients in clinical trials, particularly with higher doses. Caution should be exercised in treating patients with underlying conditions that might be compromised by increases in blood pressure (see ADVERSE REACTIONS, Vital Sign Changes). Pre-existing hypertension should be controlled before treatment with PRISTIQ. Patients receiving PRISTIQ should have regular monitoring of blood pressure. Sustained blood pressure increases could have adverse consequences. For patients who experience a sustained increase in blood pressure while receiving PRISTIQ, either dose reduction or discontinuation should be considered.

    Treatment with PRISTIQ at all doses from 50 mg/day to 400 mg/day in controlled studies was associated with sustained hypertension (defined as treatment-emergent supine diastolic blood pressure ≥ 90 mm Hg and ≥10 mm Hg above baseline for 3 consecutive visits). Table 1 provides the incidence of patients meeting criteria for sustained hypertension.


    Although desvenlafaxine succinate has not been systematically studied in preclinical or clinical trials for its potential for abuse, no indication of drug-seeking behavior was seen in the clinical trials.

    Discontinuation Symptoms

    At the time that a medical decision is made to discontinue PRISTIQ, a gradual reduction in the dose, rather than an abrupt cessation, is recommended.

    During marketing of SNRIs, and SSRIs, there have been post-marketing of adverse events occurring upon discontinuation of these drugs, particularly when abrupt, including the following: dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paraesthesias, such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia, hypomania, tinnitus, seizures, visual impairment and hypertension. While these events are generally self-limiting, there have been reports of serious discontinuation symptoms and sometimes these effects can be protracted and severe. In addition, suicide/suicidal thoughts and aggression have been observed in patients during changes in desvenlafaxine dosing regimen, including during discontinuation.

    Patients should be monitored for these symptoms when discontinuing treatment with PRISTIQ. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose but at a more gradual rate (see ADVERSE REACTIONS, Discontinuation Symptoms, and DOSAGE AND ADMINISTRATION, Discontinuing PRISTIQ). In some patients, discontinuation may need to occur over periods of months or longer.

    Endocrine and Metabolism

    Serum Cholesterol Elevation
    Increases in cholesterol (total and LDL) and triglycerides were observed in some patients treated with desvenlafaxine succinate in placebo-controlled pre-marketing clinical trials, particularly with higher doses. Measurement of serum lipid levels should be considered during treatment.

    Cases of hyponatremia and/or the Syndrome of Inappropriate Antidiuretic Hormone (SIADH) secretion have been described with SNRIs and SSRIs, usually in volume-depleted or dehydrated patients, including elderly patients and patients taking diuretics.

    Potential for Gastrointestinal Obstruction
    Because the PRISTIQ tablet does not appreciably change in shape in the gastrointestinal tract, PRISTIQ should not be administered to patients with pre-existing gastrointestinal narrowing (pathologic or iatrogenic, such as small bowel inflammatory disease, “short gut” syndrome due to adhesions or decreased transit time, past history of peritonitis, cystic fibrosis, chronic intestinal pseudo-obstruction, or Meckel’s diverticulum). There have been rare reports of obstructive symptoms in patients with known strictures in association with the ingestion of other drugs in nondeformable controlled-release formulations, and very rare reports of obstructive symptoms associated with the use of nondeformable controlled-release formulations in patients without known gastrointestinal stricture. Due to the controlled-release design, PRISTIQ tablets should only be used in patients who are able to swallow the tablets whole. (See DOSAGE AND ADMINISTRATION; Recommended Dose and Dosage Adjustment).

    Abnormal Bleeding
    SSRIs and SNRIs, including PRISTIQ, may increase the risk of bleeding events by causing abnormal platelet aggregation. Concomitant use of acetylsalicylic acid (ASA), nonsteroidal anti-inflammatory drugs (NSAIDs), warfarin and other anticoagulants may add to the risk. Case reports and epidemiological studies (case-control and cohort design) have demonstrated an association between use of drugs that interfere with serotonin reuptake and the occurrence of gastrointestinal bleeding. Bleeding events related to SSRIs and SNRIs use have ranged from ecchymoses, hematomas, epistaxis, and petechiae to life-threatening hemorrhages.

    Patients should be cautioned about the risk of bleeding associated with the concomitant use of PRISTIQ and NSAIDs, ASA, or other drugs that affect coagulation (see DRUG INTERACTIONS, Drugs Affecting Platelet Function). Caution is advised in patients with a history of bleeding disorder or predisposing conditions (e.g, thrombocytopenia).

    Interstitial Lung Disease and Eosinophilic Pneumonia

    Interstitial lung disease and eosinophilic pneumonia associated with venlafaxine (the parent drug of PRISTIQ) therapy have been rarely reported. The possibility of these adverse events should be considered in patients treated with PRISTIQ who present with progressive dyspnea, cough, or chest discomfort. Such patients should undergo a prompt medical evaluation, and discontinuation of PRISTIQ should be considered.


    Cases of seizures have been reported in trials with PRISTIQ. Desvenlafaxine succinate should be prescribed with caution in patients with a seizure disorder. Desvenlafaxine has not been systematically evaluated in patients with a seizure disorder.

    Serotonin Syndrome or Neuroleptic Malignant Syndrome (NMS)-Like Reactions
    As with other serotonergic agents, serotonin syndrome or Neuroleptic Malignant Syndrome (NMS)-like reactions, a potentially life-threatening condition, have been reported with SNRIs and SSRIs alone, including PRISTIQ treatment, particularly with concomitant use of other agents that may affect the serotonergic neurotransmitter systems (such as amphetamines, triptans, serotonin reuptake inhibitors, sibutramine, MAOIs (including linezolid, an antibiotic, and methylene blue), St. John’s Wort (Hypericum perforatum) and/or lithium) and with drugs that impair metabolism of serotonin or with antipsychotics or other dopamine antagonists. Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, and hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination) and/or gastrointestinal symptoms (e.g., nausea, vomiting, and diarrhea). Serotonin syndrome, in its most severe form, can resemble NMS, which includes hyperthermia, muscle rigidity, autonomic instability with possible rapid fluctuation of vital signs, and mental status changes.

    If concomitant treatment with desvenlafaxine and other agents that may affect the serotonergic and/or dopaminergic neurotransmitter system (such as another SSRI/SNRI) or a 5-hydroxytryptamine receptor agonist (triptan) is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases. The concomitant use of desvenlafaxine with serotonin precursors (such as tryptophan supplements) is not recommended (see DRUG INTERACTIONS, Serotonin Syndrome).

    Treatment with PRISTIQ and any concomitant serotonergic or antidopaminergic agents, including antipsychotics, should be discontinued immediately if the above events occur and supportive symptomatic treatment should be initiated.


    Angle-Closure Glaucoma
    As with other antidepressants, PRISTIQ can cause mydriasis, which may trigger an angle-closure attack in a patient with anatomically narrow ocular angles. Healthcare providers should inform patients to seek immediate medical assistance if they experience eye pain, changes in vision or swelling or redness in or around the eye.

    Mania/hypomania may occur in a small proportion of patients with mood disorders who have received medication to treat depression, including desvenlafaxine succinate. During clinical studies, mania and hypomania were reported in approximately 0.15% (12/8,453) of patients treated with PRISTIQ. Activation of mania/hypomania has also been reported in a small proportion of patients with major affective disorder who were treated with other marketed antidepressants. As with all antidepressants, PRISTIQ should be used cautiously in patients with a history or family history of mania or hypomania.

    A major depressive episode may be the initial presentation of bipolar disorder. Patients with bipolar disorder may be at an increased risk of experiencing manic episodes when treated with antidepressants alone. Therefore, the decision to initiate symptomatic treatment of depression should only be made after patients have been adequately assessed to determine if they are at risk for bipolar disorder.

    Special Populations

    Pregnant Women
    The safety of desvenlafaxine in human pregnancy has not been established. Studies have demonstrated that desvenlafaxine crosses the human placenta. The extent of exposure to PRISTIQ in pregnancy during clinical trials was very limited. There are no adequate and well-controlled studies in pregnant women. Therefore, desvenlafaxine should be used during pregnancy only if the potential benefits justify the potential risks. If desvenlafaxine succinate is used until or shortly before birth, discontinuation effects in the newborn should be considered.

    Post-marketing reports indicate that some neonates exposed to SNRIs, SSRIs, or other newer antidepressants late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyper-reflexia, tremor, jitteriness, irritability, and constant crying. These features are consistent with either a direct toxic effect of SNRIs, SSRIs and other newer antidepressants, or, possibly a drug discontinuation syndrome. It should be noted that, in some cases, the clinical picture is consistent with serotonin syndrome (see DRUG INTERACTIONS). When treating a pregnant woman with PRISTIQ during the third trimester, the physician should carefully consider the potential risks and benefits of treatment.

    Patients should be advised to notify their physician if they become pregnant or intend to become pregnant during therapy.

    Labour and Delivery
    The effect of desvenlafaxine on labour and delivery in humans is unknown. PRISTIQ should be used during labour and delivery only if the potential benefits justify the potential risks.

    Nursing Women
    Desvenlafaxine (O-desmethylvenlafaxine, a metabolite of desvenlafaxine) is excreted in human milk. The effects in infants have not been established. PRISTIQ should only be taken by breastfeeding women if the expected benefits outweigh any possible risk.

    Two placebo controlled studies in 587 pediatric patients 7 to 17 years of age with MDD failed to demonstrate efficacy; neither short term, placebo-controlled study demonstrated statistically or clinically significant differences between PRISTIQ and placebo (see WARNINGS AND PRECAUTIONS, Potential Association with Behavioural and Emotional Changes, Including Self-Harm; ACTION AND CLINICAL PHARMACOLOGY, Pediatrics).

    Geriatrics (≥ 65 years of age)
    Of the 4,158 patients in clinical trials with PRISTIQ, 6% were 65 years of age or older. No overall differences in safety or efficacy were detected between these subjects and younger subjects. However, there was a higher incidence of increases in systolic blood pressure in patients ≥ 65 years of age compared to patients < 65 years of age treated with PRISTIQ. In addition, there was a higher incidence of systolic orthostatic hypotension in patients ≥ 65 years of age compared to all adults treated with desvenlafaxine. For elderly patients, possible reduced renal clearance of desvenlafaxine should be considered when determining dose (see Dosing Considerations, Geriatrics and ACTION AND CLINICAL PHARMACOLOGY, Geriatrics). Greater sensitivity of some older individuals cannot be ruled out.

    Monitoring and Laboratory Tests

    Serum Lipids
    Increases in cholesterol (total and LDL) and triglycerides were observed in some patients treated with desvenlafaxine succinate in placebo-controlled pre-marketing clinical trials, particularly with higher doses. Measurement of serum lipid levels should be considered during treatment.

    Heart Rate and Blood Pressure
    Increases in heart rate and blood pressure were observed in some patients in clinical trials, particularly with higher doses. Measurement of blood pressure is recommended prior to initiating treatment and regularly during treatment with desvenlafaxine succinate (see ADVERSE REACTIONS, Vital Sign Changes).

    Rigorous clinical monitoring for suicidal ideation or other indicators of potential for suicidal behaviour is advised in patients of all ages. Patients, their families, and their caregivers should be encouraged to be alert to the emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, mania, other unusual changes in behavior, worsening of depression, and suicidal ideation, especially when initiating therapy or during any change in dose or dosage regimen. (See WARNINGS AND PRECAUTIONS, POTENTIAL ASSOCIATION WITH BEHAVIOURAL AND EMOTIONAL CHANGES, INCLUDING SELF-HARM).

    Generic Name: desvenlafaxine

    Medically reviewed by Last updated on Nov 1, 2018.

    • Overview
    • Side Effects
    • Dosage
    • Professional
    • Interactions
    • More

    Note: This document contains side effect information about desvenlafaxine. Some of the dosage forms listed on this page may not apply to the brand name Pristiq.

    In Summary

    Common side effects of Pristiq include: constipation, dizziness, drowsiness, insomnia, nausea, decreased appetite, hyperhidrosis, and xerostomia. Other side effects include: anxiety, blurred vision, mydriasis, tremor, vertigo, vomiting, abnormal dreams, chills, and yawning. See below for a comprehensive list of adverse effects.

    For the Consumer

    Applies to desvenlafaxine: oral tablet extended release


    Oral route (Tablet, Extended Release)

    Antidepressant use has been associated with an increased risk of suicidal thinking and behavior in children, adolescents, and young adults. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared with placebo in adults beyond age 24, and there was a reduction in risk with antidepressants compared with placebo in adults aged 65 or older. Monitor patients closely for clinical worsening, suicidality, or unusual changes in behavior. Desvenlafaxine is not approved for use in pediatric patients.

    Oral route (Tablet, Extended Release)

    Antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults during short-term studies. These studies did not show an increase in the risk of suicidality with antidepressants compared with placebo in adults older than 24 years, and there was a reduction in risk with antidepressants compared with placebo in adults aged 65 or older. Monitor patients closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Not approved for use in pediatric patients.

    Along with its needed effects, desvenlafaxine (the active ingredient contained in Pristiq) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

    Check with your doctor immediately if any of the following side effects occur while taking desvenlafaxine:

    Less common

    • Chills
    • cold sweats
    • confusion
    • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
    • fast, pounding, or irregular pulse
    • headache
    • numbness or tingling in the arms or legs
    • shakiness in the legs, arms, hands, or feet
    • trouble thinking, speaking, or walking
    • weakness

    Incidence not known

    • Blistering, peeling, or loosening of the skin
    • blood in the stool or urine
    • chest tightness
    • cough
    • diarrhea
    • dilated or enlarged pupils (black part of the eye)
    • feeling irritated
    • fever
    • hives, itching, or rash
    • hoarseness
    • joint pain, stiffness, or swelling
    • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
    • loss of bladder control
    • muscle pain
    • muscle spasm or jerking of all extremities
    • nosebleeds
    • red skin lesions, often with a purple center
    • red, irritated eyes
    • red skin
    • seizures
    • sore throat
    • sores, ulcers, or white spots in the mouth or on the lips
    • sudden loss of consciousness
    • swelling of the eyelids, face, lips, hands, or feet
    • talking, feeling, or acting with excitement
    • trouble breathing or swallowing
    • unusual bruising
    • unusual tiredness or weakness
    • vomiting blood

    Get emergency help immediately if any of the following symptoms of overdose occur while taking desvenlafaxine:

    Symptoms of overdose

    • Agitation
    • bloating
    • dark urine
    • feeling of constant movement of self or surroundings
    • irregular heartbeat recurrent
    • light-colored stools
    • muscle cramp or stiffness
    • nausea
    • overactive reflexes
    • poor coordination
    • restlessness
    • seizures
    • sensation of spinning
    • shivering
    • stomach pain
    • vomiting
    • yellow eyes or skin

    Some side effects of desvenlafaxine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

    More common

    • Decreased appetite
    • inability to have an orgasm
    • inability to have or keep an erection
    • increased sensitivity of the eyes to light
    • loss of sexual ability, desire, drive, or performance
    • sleepiness or unusual drowsiness
    • sleeplessness

    Less common

    • Change in taste
    • continuous ringing, buzzing, or other unexplained noise in the ears
    • decreased weight
    • difficult urination
    • fear or nervousness
    • hearing loss
    • jitteriness
    • lack or loss of strength
    • loss of taste

    For Healthcare Professionals

    Applies to desvenlafaxine: oral tablet extended release

    The most commonly reported side effects were nausea, dry mouth, hyperhidrosis, and dizziness.


    Very Common (10% or more): Nausea (up to 36%), dry mouth (up to 25%), constipation (up to 14%)

    Common (1% to 10%): Diarrhea, vomiting

    Rare (less than 0.1%): Acute pancreatitis

    Frequency not reported: Gastrointestinal bleeding


    Very Common (10% or more): Hyperhidrosis (up to 21%)

    Common (1% to 10%): Rash

    Uncommon (0.1% to 1%): Alopecia

    Rare (less than 0.1%): Photosensitivity reaction, Stevens-Johnson syndrome

    Frequency not reported: Erythema multiforme, severe cutaneous reactions, toxic epidermal necrolysis

    Nervous system

    Very Common (10% or more): Dizziness (up to 16%), somnolence (up to 12%)

    Common (1% to 10%): Disturbance in attention, dysgeusia, headache, paresthesia, tremor, vertigo

    Uncommon (0.1% to 1%): Dyskinesia, extrapyramidal disorder, syncope

    Rare (less than 0.1%): Convulsion, dystonia, serotonin syndrome

    Frequency not reported: Seizure


    Very common (10% or more): Insomnia (up to 15%)

    Uncommon (0.1% to 1%): Depersonalization, hypomania

    Rare (less than 0.1%): Hallucination, mania

    Frequency not reported: Bruxism, discontinuation syndrome, suicidal thoughts


    Very Common (10% or more): Erectile dysfunction (up to 11%)

    Common (1% to 10%): Delayed ejaculation, ejaculation disorder, ejaculation failure, proteinuria, sexual dysfunction, urinary hesitation

    Uncommon (0.1% to 1%): Urinary retention


    Very Common (10% or more): Fatigue (up to 11%)

    Common (1% to 10%): Asthenia, chills, feeling jittery, tinnitus


    Common (1% to 10%): Decreased appetite, decreased weight, elevated fasting triglycerides, elevated LDL cholesterol, elevated total cholesterol, increased blood cholesterol, increased weight

    Uncommon (0.1% to 1%): Increased blood triglycerides

    Rare (less than 0.1%): Hyponatremia


    Ischemic cardiac adverse reactions, myocardial ischemia, myocardial infarction, and/or coronary occlusion requiring revascularization usually occurred in patients who had multiple underlying cardiac risk factors.

    Common (1% to 10%): Blood pressure increased, hot flush, increased sustained hypertension, orthostatic hypotension, palpitations, tachycardia

    Uncommon (0.1% to 1%): Peripheral coldness

    Frequency not reported: Coronary occlusion requiring revascularization, ischemic cardiac adverse reactions, myocardial infarction, myocardial ischemia


    Common (1% to 10%): Blurred vision, mydriasis

    Frequency not reported: Angle closure glaucoma


    Common (1% to 10%): Yawning

    Uncommon (0.1% to 1%): Epistaxis

    Frequency not reported: Interstitial lung disease, eosinophilic pneumonia


    Common (1% to 10%): Abnormal liver function test


    Common (1% to 10%): Musculoskeletal stiffness


    Uncommon (0.1% to 1%): Hypersensitivity

    Rare (less than 0.1%): Angioedema


    Uncommon (0.1% to 1%): Increased blood prolactin


    Frequency not reported: Abnormal bleeding

    1. “Product Information. Pristiq (desvenlafaxine).” Wyeth Laboratories, Philadelphia, PA.

    2. Cerner Multum, Inc. “Australian Product Information.” O 0

    Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

    Some side effects may not be reported. You may report them to the FDA.

    Medical Disclaimer

    Generic Name: Desvenlafaxine (des VEN la FAX een)

    Brand name: Pristiq

    Drug Class: Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)

    Table of Contents

    • Overview
    • How to Take It
    • Side Effects
    • Warnings & Precautions
    • Drug Interactions
    • Dosage & Missing a Dose
    • Storage
    • Pregnancy or Nursing
    • More Information


    Pristiq (Desvenlafaxine) is an antidepressant in used to treat major depressive disorder. It belongs to a group of drugs called selective serotonin and norepinephrine reuptake inhibitors (SNRIs). This medication affects chemicals in the brain that be unbalanced in people with depression.

    It works by restoring the balance of certain naturally-occurring substances in the brain (serotonin and norepinephrine).

    This information is for educational purposes only. Not every known side effect, adverse effect, or drug interaction is in this database. If you have questions about your medicines, talk to your health care provider.

    How to Take It

    Take this medicine as directed. It can be taken with or without food. Do not stop taking this medicine abruptly without consulting with your doctor.

    Side Effects

    Side effects that may occur while taking this medicine include:

    • excessive sweating
    • nervousness
    • vertigo
    • dizziness
    • chills
    • unusual dreams
    • blurred vision

    Contact your doctor if you experience symptoms that become bothersome, including:

    • severe headache
    • difficulty urinating
    • rash
    • trouble speaking
    • seizures
    • uncontrollable shaking
    • confusion
    • fever
    • changes in sexual ability

    Warnings & Precautions

    • If you have taken an MAO inhibitor in the past two weeks, DO NOT not use Pristiq. A dangerous drug interaction could occur.
    • Pristiq may raise your blood pressure. Check your blood pressure regularly and inform your physician if the results are high.
    • Inform your doctor or dentist that you are taking this drug if you are having any type of surgery.
    • Seek medical attention immediately if you experience serious side effects, including eye pain or swelling, persistent cough, black stools, shortness of breath, chest pain, vomit that looks like coffee grounds, change in the amount of urine, seizures, or any vision changes.
    • Talk to your doctor about having an eye examination before you start taking this medication. Desvenlafaxine may cause angle-closure glaucoma, a condition which may lead to a loss of vision.
    • For an overdose, seek medical attention immediately. For non emergencies, contact your local or regional poison control center at 1-800-222-1222.

    Drug Interactions

    Before taking any new medicine, either prescription or over-the-counter, check with your doctor or pharmacist. This includes supplements and herbal products.

    Dosage & Missed Dose

    Follow all directions exactly as prescribed by your doctor. The recommended dose is 50 mg daily. This medication should be swallowed whole.

    Do not chew, crush, or dissolve this medication in water. Doing so can release all of the drug at once, increasing the risk of side effects. Do not split the tablets unless advised by your doctor to do so.

    If you skip a dose, take your next dose as soon as you remember. If it is time for your next dose, skip the missed dose and go back to your regular schedule. Do not double doses or take extra medicine to make up for the missed dose.


    Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (preferably not in the bathroom). Throw away any medication that is outdated or no longer needed.


    This medication should only be used when necessary. Taking this medication, particularly in the last three months of pregnancy, can muscle stiffness, constant crying, drowsiness, or feeding or breathing difficulties in a newborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

    This medication passes into breast milk and could have harmful effects on a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

    More Information


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