Side effects of intuniv

Contents

What Is Intuniv (Guanfacine)?

Intuniv (generic name: guanfacine) is a once-daily, non-stimulant ADHD medication approved to treat attention deficit hyperactivity disorder (ADHD or ADD) in children ages 6-12, and adolescents. Although only studied and approved in children and adolescents, Intuniv is commonly used off-label by all ages.

Intuniv is most commonly used as an add-on to a finely tuned stimulant medication. It can be used by itself as a monotherapy when people do not get benefits from the stimulant medications, do not tolerate the stimulant medications, or decline the use of stimulant class medications.

How Does Intuniv (Guanfacine) Work to Treat ADHD Symptoms?

Intuniv is a central alpha2A-adrenergic receptor agonist that is thought to address major areas of impairment and ADHD symptoms such as emotional sensitivity, hyperarousal, rejection sensitivity and social aggression that are not addressed by stimulant medications . Thus, non-stimulant medications like Intuniv sometimes help patients with ADHD who can’t take or don’t experience benefits from stimulants.The alpha agonists treat the impairments that stimulants do not treat well by lowering the adrenaline side of the nervous system so that its level is the same as a person who does not have ADHD.

Intuniv has not been studied in children younger than 6. Intuniv does not have a high risk of abuse or dependence. It is not a controlled substance.

The two alpha agonists available in the United States were originally brought to the market in the early 1980’s as medications to lower blood pressure. In practice, the alpha agonists are not very effective for blood pressure so low blood pressure is rarely a major side effect of this category of medications. Their primary FDA-approved use now is to treat the hyperarousal component of ADHD.

How Do You Use Intuniv (Guanfacine) to Treat ADHD?

Before starting or refilling an Intuniv prescription, read the medication guide included with your pills, as it may be updated with new information.

This guide should not replace a conversation with your doctor, who has a holistic view of your or your child’s medical history, other diagnoses, and other prescriptions. If you have questions, ask your doctor or pharmacist before you begin taking the medication.

What Dosage of Intuniv Is Used to Treat ADHD?

As with all medications, follow your Intuniv prescription instructions exactly. Intuniv is an extended-release tablet taken once daily in the morning or evening at approximately the same time each day. Tablets are available in 1mg, 2mg, 3mg, and 4mg dosages.

Intuniv should not be taken with a high-fat meal. This can speed up the release of medication, and increase the risk of side effects. Tablets should be swallowed whole, and never crushed or chewed.

The optimal dosage varies patient by patient. Your doctor may adjust your dosage weekly by 1 mg to the dose at which you experience the greatest improvement in symptoms without side effects. Fine-tuning the dose of either alpha agonist will take several weeks. Unlike the stimulant medications that are immediately effective in just an hour or so, the alpha agonists such as Intuniv take 5 days for their benefits to develop each time the dose is increased. During the process of fine-tuning the dose the fastest that each step can be taken is every 5th day. This also means that Intuniv must be taken every day. If a person misses several doses, the benefits are lost and the person has to start over again and wait 5 days for the benefits to develop once more.”

Do not drink alcohol while taking this drug.

As with all medications, drugs like Intuniv should not be stopped suddenly or without prior consultation with a clinician.

What Are the Side Effects of Intuniv?

The FDA cites the following side effects of Intuniv:

  • sleepiness
  • dry mouth
  • tiredness
  • difficulty sleeping
  • nausea
  • stomach pain
  • dizziness
  • irritability
  • vomiting
  • slow heart rate
  • low blood pressure

Other serious side effects of Intuniv include

  • low blood pressure
  • low heart rate
  • fainting
  • sleepiness
  • increased blood pressure and heart rate or other withdrawal symptoms after suddenly stopping IntunIn practice, three major side effects are reported by clinicians with any frequency:
    1. Mild sedation / sleepiness in about 25% of people
    2. Dry mouth that usually goes away in about 2 weeks in about 20% of people
    3. An accentuation of the experience of standing up quickly and getting lightheaded, dizzy, and vision turning somewhat gray. This universal experience can increase in frequency in about 10% of people who take Intuniv.

Paradoxically both of the alpha agonists can cause difficulty sleeping and severe irritability in about 1-2% of people. Neither of these side effects go away with time so, if they occur, the Intuniv will need to be stopped.

Taking Intuniv may impair your or your teenager’s ability to drive, operate machinery, or perform other potentially dangerous tasks. If side effects are bothersome, or do not go away, talk to your doctor. Most people taking this medication do not experience any of these side effects.

Report to your doctor any heart-related problems or a family history of heart and blood pressure problems. Patients with structural cardiac abnormalities, renal failure, and serious heart problems could experience complications while taking Intuniv. Physicians should monitor these vital signs closely during treatment. Call your doctor immediately if you or your child experience warning signs such as chest pain, shortness of breath, or fainting while taking Intuniv.

The above is not a complete list of potential side effects. If you notice any health changes not listed above, discuss them with your doctor or pharmacist.

What Precautions Are Associated with Intuniv?

Store Intuniv in a secure place out of the reach of children, and at room temperature. Do not share your Intuniv prescription with anyone, even another person with ADHD. Sharing prescription medication is illegal, and can cause harm.

You should not take Intuniv if you have an allergy to Intuniv or any of its ingredients. You should use caution taking Intuniv if you have kidney problems, a history of fainting, heart problems, or a history of stroke.

Avoid becoming overheated or dehydrated while taking Intuniv.

If you’re thinking of having a child, discuss the use of Intuniv with your doctor. Animal studies indicate a potential risk of fetal harm. It is not known if Intuniv is passed through breastmilk, so it is recommended that mothers do not nurse while taking it.

What Interactions Are Associated with Intuniv?

Before taking Intuniv, discuss all other active prescription medications with your doctor. Intuniv can exacerbate the drowsiness created by depressants including alcohol, barbiturates, antihistamines, or other sedatives.

Share a list of all vitamin or herbal supplements, and prescription and non-prescription medications you take with the pharmacist when you fill your prescription, and let all doctors and physicians know you are taking Intuniv before having any surgery or laboratory tests. The above is not a complete list of all possible drug interactions.

Generic Name: guanfacine (GWAHN fa seen)
Brand Names: Intuniv, Tenex

Medically reviewed by Sanjai Sinha, MD Last updated on Mar 15, 2019.

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What is Intuniv?

Intuniv (guanfacine) reduces nerve impulses in your heart and blood vessels. Intuniv works by relaxing blood vessels, which lowers blood pressure and improves blood flow.

Intuniv is a prescription medicine used to treat attention deficit hyperactivity disorder (ADHD) in children who are at least 6 years old.

Intuniv is a long acting tablet that is taken once daily, normally in the morning, at approximately the same time each day.

The Tenex brand of guanfacine is used to treat high blood pressure (hypertension). It is sometimes given with other blood pressure medications.

Important Information

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Avoid becoming overheated or dehydrated during excercise and in hot weather. Avoid drinking alcohol.

Tell your doctor if you regularly use other medicines that make you sleepy. They can add to sleepiness caused by Intuniv.

Before taking this medicine

You should not use Intuniv if you are allergic to guanfacine.

Intuniv is not approved for use by anyone younger than 6 years old.

Tell your doctor if you have ever had:

  • heart problems, coronary artery disease (clogged arteries);

  • a heart rhythm disorder;

  • a heart attack or stroke;

  • high or low blood pressure;

  • liver disease; or

  • kidney disease.

It is not known whether Intuniv will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breast-feed a baby while you are using this medicine. Ask your doctor about any risks.

How should I take Intuniv?

Take Intuniv exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Take Intuniv with a full glass of water, milk, or other liquid.

Swallow the Intuniv tablet whole and do not crush, chew, or break it.

If a child is using this medicine, tell your doctor if the child has any changes in weight. Guanfacine doses are based on weight in children, and any changes may affect your child’s dose.

You should not stop using Intuniv suddenly. Stopping suddenly can raise your blood pressure and cause unpleasant symptoms.

Call your doctor if you are sick with vomiting and cannot take your medicine as usual.

Your dose needs may change if you switch to a different brand, strength, or form of this medicine. Avoid medication errors by using only the form and strength your doctor prescribes.

Your doctor will need to check your progress on a regular basis. Your blood pressure and heart rate may also need to be checked.

Store at room temperature away from moisture, heat, and light.

Intuniv dosing information

Usual Pediatric Dose for Attention Deficit Disorder:

6 YEARS TO LESS THAN 18 YEARS:
Initial dose: 1 mg orally once a day, either in the morning or evening, at approximately the same time each day; may adjust in increments of no more than 1 mg/week.
Recommended target dose: 0.05 to 0.12 mg/kg/day (total daily dose between 1 and 7 mg) once a day, depending on clinical response and tolerability
Maximum dose: 6 to 12 years: Doses above 4 mg/day have not been evaluated; 13 to 17 years: Doses above 7 mg/day have not been evaluated.
Comments: Attention Deficit Hyperactivity Disorder (ADHD) may require treatment for an extended period of time; healthcare providers should periodically reevaluate treatment and adjust dose as needed.
Use: Treatment of ADHD as monotherapy and as adjunctive therapy to stimulant medications.

What happens if I miss a dose?

Avoid taking Intuniv with high-fat foods, or your body could absorb the medicine too quickly.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Call your doctor for instructions if you miss more than 2 doses in a row.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include severe drowsiness, slow heart rate, and feeling like you might pass out.

What should I avoid while taking Intuniv?

Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.

Drinking alcohol can increase certain side effects of Intuniv.

Intuniv side effects

Get emergency medical help if you have signs of an allergic reaction to Intuniv: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • anxiety, nervousness;

  • hallucinations (especially in children);

  • severe drowsiness;

  • slow heartbeats; or

  • a light-headed feeling, like you might pass out;

If you stop taking Intuniv, tell your doctor if you have headaches, confusion, rapid heartbeats, tremors, increased blood pressure, or if you feel nervous or agitated. If left untreated, these symptoms could lead to very high blood pressure, vision problems, or seizures.

Common Intuniv side effects may include:

  • dizziness, drowsiness;

  • low blood pressure, slow heartbeats;

  • feeling tired or irritable;

  • trouble sleeping;

  • dry mouth; or

  • stomach pain, nausea, constipation.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Intuniv?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Using Intuniv with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety, depression, or seizures.

Tell your doctor about all your other medicines. Some may affect Intuniv, especially:

  • ketoconazole;

  • a barbiturate, such as phenobarbital;

  • blood pressure medications;

  • medicine to treat mental illness; or

  • a sedative, such as Valium or Xanax.

This list is not complete. Other drugs may interact with guanfacine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Intuniv only for the indication prescribed.

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

Copyright 1996-2020 Cerner Multum, Inc. Version: 11.01.

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SIDE EFFECTS

The following serious adverse reactions are described elsewhere in the labeling:

  • Hypotension, bradycardia, and syncope
  • Sedation and somnolence
  • Cardiac conduction abnormalities
  • Rebound Hypertension

Clinical Trials 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 trials of another drug and may not reflect the rates observed in practice.

The data described below reflect clinical trial exposure to INTUNIV® in 2,825 patients. This includes 2,330 patients from completed studies in children and adolescents, ages 6 to 17 years and 495 patients in completed studies in adult healthy volunteers.

The mean duration of exposure of 446 patients that previously participated in two 2-year, open-label long-term studies was approximately 10 months.

Fixed Dose Trials

Table 3: Percentage of Patients Experiencing Most Common (≥5% and at least twice the rate for placebo) Adverse Reactions in Fixed Dose Studies 1 and 2

Table 4: Adverse Reactions Leading to Discontinuation (≥2% for all doses of INTUNIV and >rate than in placebo) in Fixed Dose Studies 1 and 2

Table 5: Other Common Adverse Reactions (≥2% for all doses of INTUNIV and >rate than in placebo) in Fixed Dose Studies 1 and 2

Monotherapy Flexible Dose Trials

Table 6: Percentage of Patients Experiencing Most Common (≥5% and at least twice the rate for placebo) Adverse Reactions in the Monotherapy Flexible Dose Study 4

Table 7: Adverse Reactions Leading to Discontinuation (≥2% for all doses of INTUNIV and >rate than in placebo) in Monotherapy Flexible Dose Study 4

Table 8: Other Common Adverse Reactions (≥2% for all doses of INTUNIV and >rate than in placebo) in the Monotherapy Flexible Dose Study 4

Table 9: Percentage of Patients Experiencing Most Common (≥ 5% and at least twice the rate for placebo) Adverse Reactions in the Monotherapy Flexible Dose Study 5

Adverse Reaction Term Placebo
(N=155)
All Doses of INTUNIV®
(N=157)
Somnolencea 23% 54%
Insomniab 6% 13%
Hypotensionc 3% 9%
Dry Mouth 0% 8%
Postural Dizziness 2% 5%
Bradycardiad 0% 5%
a The somnolence term includes somnolence, sedation, and hypersomnia.
b The insomnia term includes insomnia, initial insomnia, middle insomnia, terminal insomnia, and sleep disorder.
c The hypotension term includes hypotension, diastolic hypotension, orthostatic hypotension, blood pressure decreased, blood pressure diastolic decreased, blood pressure systolic decreased).
d The bradycardia term includes bradycardia and sinus bradycardia.

There were no specific adverse reactions ≥2% in any treatment group that led to discontinuation in the monotherapy flexible dose study (Study 5).

Table 10: Other Common Adverse Reactions (≥2% for all doses of INTUNIV and >rate than in placebo) in the Monotherapy Flexible Dose Study 5

Adverse Reaction Term Placebo
(N=155)
INTUNIV® All Doses of INTUNIV®
(N=157)
Headache 18% 27%
Fatigue 12% 22%
Dizziness 10% 16%
Decreased Appetite 14% 15%
Abdominal Paina 8% 12%
Irritability 4% 7%
Anxietyb 3% 5%
Rashc 1% 3%
Constipation 0% 3%
Increased Weight 2% 3%
Abdominal/Stomach Discomfortd 1% 2%
Pruritus 1% 2%
Adverse reactions ≥2% for all doses of INTUNIV and >rate in placebo in any dose group but did not meet this criteria in all doses combined: nausea, diarrhea, vomiting, and depression (depressed mood, depression, depressive symptom).
a The abdominal pain term includes abdominal pain, abdominal pain lower, abdominal pain upper, and abdominal tenderness.
b The anxiety term includes anxiety and nervousness.
c The rash term includes rash, rash generalized, and rash papular.
d The abdominal/stomach discomfort term includes abdominal discomfort, epigastric discomfort, and stomach discomfort.

Adjunctive Trial

Table 11: Percentage of Patients Experiencing Most Common (≥5% and at least twice the rate for placebo) Adverse Reactions in the Short-Term Adjunctive Study 3

There were no specific adverse reactions ≥2% in any treatment group that led to discontinuation in the short-term adjunctive study (Study 3).

Table 12: Other Common Adverse Reactions (≥2% for all doses of INTUNIV and >rate than in placebo) in the Short-Term Adjunctive Study 3

Adverse Reaction Term Placebo
(N=153)
INTUNIV® + stimulant
AM
(N=150)
PM
(N=152)
All Doses of INTUNIV®
(N=302)
Headache 13% 21% 21% 21%
Diarrhea 1% 4% 3% 4%
Hypotensiona 0% 4% 2% 3%
Constipation 0% 2% 3% 2%
Affect Labilityb 1% 3% 2% 2%
Dry Mouth 0% 1% 3% 2%
Bradycardiac 0% 1% 3% 2%
Postural Dizziness 0% 1% 3% 2%
Rashd 1% 1% 2% 2%
Nightmaree 1% 2% 1% 2%
Tachycardiaf 1% 2% 1% 2%
Adverse reactions ≥2% for all doses of INTUNIV and >rate in placebo in any dose group but did not meet this criteria in all doses combined: irritability, vomiting, asthma (asthma, bronchospasm, wheezing), and enuresis (enuresis, nocturia, urinary incontinence).
a The hypotension term includes hypotension, diastolic hypotension, orthostatic hypotension, blood pressure decreased, blood pressure diastolic decreased, blood pressure systolic decreased.
b The affect lability term includes affect lability and mood swings.
c The bradycardia term includes bradycardia and sinus bradycardia.
d The rash term includes rash, rash generalized, and rash papular.
e The nightmare term includes abnormal dreams, nightmare, and sleep terror.
f The tachycardia term includes tachycardia and sinus tachycardia.

Effects On Blood Pressure And Heart Rate

In the monotherapy pediatric, short-term, controlled trials (Studies 1 and 2), the maximum mean changes from baseline in seated systolic blood pressure, diastolic blood pressure, and pulse were -5.4 mmHg, -3.4 mmHg, and -5.5 bpm, respectively, for all doses combined (generally one week after reaching target doses). For the respective fixed doses 1 mg/day, 2 mg/day, 3 mg/day or 4 mg/day the maximum mean changes in seated systolic blood pressure were -4.3 mmHg, -5.5 mmHg, -5.4 mmHg and -8.2 mmHg. For these respective fixed doses the maximum mean changes in seated diastolic blood pressure were -3.4 mmHg, -3.3 mmHg, -4.4 mmHg and -5.4 mmHg. For these respective fixed doses the maximum mean changes in seated pulse were -4.8 bpm, -3.1 bpm, -6.5 bpm and -8.6 bpm. Decreases in blood pressure and heart rate were usually modest and asymptomatic; however, hypotension and bradycardia can occur. Hypotension was reported as an adverse reaction for 7% of the INTUNIV® group and 3% of the placebo group. This includes orthostatic hypotension, which was reported for 1% of the INTUNIV® group and none in the placebo group. These findings were generally similar in the monotherapy flexible dose trials (Studies 4 and 5). In the adjunctive trial, hypotension (3%) and bradycardia (2%) were observed in patients treated with INTUNIV® as compared to none in the placebo group. In long-term, open-label studies, (mean exposure of approximately 10 months), maximum decreases in systolic and diastolic blood pressure occurred in the first month of therapy. Decreases were less pronounced over time. Syncope occurred in 1% of pediatric patients in the clinical program. The majority of these cases occurred in the long-term, open-label studies.

Discontinuation Of Treatment

Blood pressure and pulse may increase above baseline values following discontinuation of INTUNIV®. In five studies of children and adolescents , increases in mean systolic and diastolic blood pressure averaging approximately 3 mmHg and increases in heart rate averaging 5 beats per minute above original baseline were observed upon discontinuation with tapering of INTUNIV+. In a maintenance of efficacy study, increases in blood pressure and heart rate above baseline slowly diminished over the follow up period, which ranged between 3 and 26 weeks post final dose; the estimated average time to return to baseline was between six and twelve months. In this study, the increases in blood pressure and pulse were not considered serious or associated with adverse events. However, individuals may have larger increases than reflected by the mean changes.

In postmarketing experience, following abrupt discontinuation of INTUNIV®, rebound hypertension and hypertensive encephalopathy have been reported .

Effects On Height, Weight, And Body Mass Index (BMI)

Patients taking INTUNIV® demonstrated similar growth compared to normative data. Patients taking INTUNIV® had a mean increase in weight of 0.5 kg compared to those receiving placebo over a comparable treatment period. Patients receiving INTUNIV® for at least 12 months in open-label studies gained an average of 8 kg in weight and 8 cm (3 in) in height. The height, weight, and BMI percentile remained stable in patients at 12 months in the long-term studies compared to when they began receiving INTUNIV®.

Other Adverse Reactions Observed In Clinical Studies

Table 13 includes additional adverse reactions observed in short-term, placebo-controlled and long-term, open-label clinical studies not included elsewhere in section 6.1, listed by organ system.

Table 13: Other adverse reactions observed in clinical studies

Body System Adverse Reaction
Cardiac Atrioventricular block
General Asthenia, chest pain
Immune System Disorders Hypersensitivity
Investigations Increased alanine amino transferase
Nervous system Convulsion
Renal Increased urinary frequency
Vascular Hypertension, pallor

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of guanfacine. 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.

Less frequent, possibly guanfacine-related events observed in the post-marketing study and/or reported spontaneously, not included in section 6.1, include:

General: edema, malaise, tremor

Cardiovascular: palpitations, tachycardia, rebound hypertension, hypertensive encephalopathy

Central Nervous System: paresthesias, vertigo

Eye Disorders: blurred vision

Musculo-Skeletal System: arthralgia, leg cramps, leg pain, myalgia

Psychiatric: confusion, hallucinations

Reproductive System, Male: impotence

Respiratory System: dyspnea

Skin and Appendages: alopecia, dermatitis, exfoliative dermatitis, pruritus, rash

Special Senses: alterations in taste

Read the entire FDA prescribing information for Intuniv (guanfacine)

Treatment


Attention deficit hyperactivity disorder (ADHD)

Methylphenidate

Methylphenidate is the most commonly used medication for ADHD. It belongs to a group of medicines called stimulants, which work by increasing activity in the brain, particularly in areas that play a part in controlling attention and behaviour.

Methylphenidate may be offered to adults, teenagers and children over the age of 5 with ADHD.

The medication can be taken as either immediate-release tablets (small doses taken 2 to 3 times a day) or as modified-release tablets (taken once a day in the morning, with the dose released throughout the day).

Common side effects of methylphenidate include:

  • a small increase in blood pressure and heart rate
  • loss of appetite, which can lead to weight loss or poor weight gain
  • trouble sleeping
  • headaches
  • stomach aches
  • mood swings

Lisdexamfetamine

Lisdexamfetamine is a similar medication to dexamfetamine and works in the same way.

It may be offered to teenagers and children over the age of 5 with ADHD if at least 6 weeks of treatment with methylphenidate has not helped. Adults may be offered lisdexamfetamine as the first-choice medication instead of methylphenidate.

Lisdexamfetamine comes in capsule form, taken once a day.

Common side effects of lisdexamfetamine include:

  • decreased appetite, which can lead to weight loss or poor weight gain
  • aggression
  • drowsiness
  • dizziness
  • headaches
  • diarrhoea
  • nausea and vomiting

Dexamfetamine

Dexamfetamine is similar to lisdexamfetamine and works in the same way. It may be offered to adults, teenagers and children over the age of 5 with ADHD.

Dexamfetamine is usually taken as a tablet once or twice a day, although an oral solution is also available.

Common side effects of dexamfetamine include:

  • decreased appetite
  • mood swings
  • agitation and aggression
  • dizziness
  • headaches
  • diarrhoea
  • nausea and vomiting

Atomoxetine

Atomoxetine works differently from other ADHD medications.

It’s a selective noradrenaline reuptake inhibitor (SNRI), which means it increases the amount of a chemical in the brain called noradrenaline.

This chemical passes messages between brain cells, and increasing it can aid concentration and help control impulses.

Atomoxetine may be offered to adults, teenagers and children over the age of 5 if it’s not possible to use methylphenidate or lisdexamfetamine. It’s also licensed for use in adults if symptoms of ADHD are confirmed.

Atomoxetine comes in capsule form, usually taken once or twice a day.

Common side effects of atomoxetine include:

  • a small increase in blood pressure and heart rate
  • nausea and vomiting
  • stomach aches
  • trouble sleeping
  • dizziness
  • headaches
  • irritability

Atomoxetine has also been linked to some more serious side effects that are important to look out for, including suicidal thoughts and liver damage.

If either you or your child begin to feel depressed or suicidal while taking this medication, speak to your doctor.

Guanfacine acts on part of the brain to improve attention, and it also reduces blood pressure.

It may be offered to teenagers and children over the age of 5 if it’s not possible to use methylphenidate or lisdexamfetamine. Guanfacine should not be offered to adults with ADHD.

Guanfacine is usually taken as a tablet once a day, in the morning or evening.

Common side effects include:

  • tiredness or fatigue
  • headache
  • abdominal pain
  • dry mouth

Intuniv: Answers to Your ADHD Medication Questions

Intuniv for ADHD Symptoms

Considering treating your child’s attention deficit hyperactivity disorder (ADHD or ADD) with Intuniv? William Dodson, M.D., answers frequently asked questions about this nonstimulant ADHD medication.

Which ADHD symptoms does Intuniv help treat?

I use stimulants for performance enhancement in school and work settings. But stimulants don’t touch some symptoms of ADHD that impair patients’ lives: emotional sensitivity, an inner sense of hyperarousal that makes people uncomfortable in their own skin, social aggressiveness, especially in kids. Intuniv does a good job with these symptoms, largely without side effects.

How effective is Intuniv at treating ADHD in children?

About 70 percent of people who take Intuniv for ADHD get robust benefits, and we don’t know, in advance of taking it, who will respond well. A person has to try the medication. It typically takes a week to find out if it will help. The benefits accrue over time. Twenty percent of people won’t see any benefit and may feel crummy. About 10 percent experience irritability from the first dose. In my experience, the irritability doesn’t wear off, and I tell affected patients to stop taking it.

How has Intuniv worked for your patients with ADD?

I started out as a skeptic about Intuniv — a time-release version of the alpha-2 agonist guanfacine — but my ADHD patients’ favorable responses have made me an advocate for it. I prescribe it for all age groups, not just the six- to 17-year-old group for which the FDA approved it. I almost always use it as an adjunct to a stimulant.

What makes Intuniv different from other ADHD medications?

The time-release kinetics of Intuniv make the difference. The quick absorption of immediate-release guanfacine causes the nervous system to fight the effects of the medication — or immediate-release stimulants, for that matter — when it is released, in a rush, into the bloodstream. You experience that “fight” as side effects. The extended, gradual release of Intuniv doesn’t seem to elicit this reaction in the nervous system.

Is there a difference between generic guanfacine and Intuniv? How do they compare?

The first people I prescribed Intuniv to had been taking guanfacine for several years. With the exception of one person, they came back saying, “I love this new medication, but tell me, What is it really? I’ve been taking guanfacine, and this isn’t guanfacine.”

What are common side effects of Intuniv?

  • sleepiness
  • dry mouth
  • tiredness
  • difficulty sleeping
  • nausea
  • stomach pain
  • dizziness
  • irritability
  • vomiting
  • slow heart rate
  • low blood pressure

Other serious side effects of Intuniv include:

  • low blood pressure
  • low heart rate
  • fainting
  • sleepiness
  • increased blood pressure and heart rate or other withdrawal symptoms after suddenly stopping Intuniv

Taking Intuniv may impair your or your teenager’s ability to drive, operate machinery, or perform other potentially dangerous tasks. If side effects are bothersome, or do not go away, talk to your doctor. Most people taking this medication do not experience any of these side effects.

Report to your doctor any heart-related problems or a family history of heart and blood pressure problems. Patients with structural cardiac abnormalities, renal failure, and serious heart problems could experience complications while taking Intuniv. Physicians should monitor these vital signs closely during treatment. Call your doctor immediately if you or your child experience warning signs such as chest pain, shortness of breath, or fainting while taking Intuniv.

The above is not a complete list of potential side effects. If you notice any health changes not listed above, discuss them with your doctor or pharmacist.

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Updated on January 18, 2019

Guanfacine (Intuniv) for Attention-Deficit/Hyperactivity Disorder

SAFETY

Guanfacine can cause hypotension, although it does not cause symptoms in most patients, and changes in blood pressure are usually small. Approximately 1 percent of children taking guanfacine will experience orthostatic hypotension. Syncope also occurs in about 1 percent of children, but it is not clear whether this is related to the drop in blood pressure or is a separate adverse effect. Changes on electrocardiography, including bradycardia, are rare but have occurred in clinical trials. Abrupt withdrawal of guanfacine should be avoided to decrease the risk of notable changes in blood pressure. Guanfacine is U.S. Food and Drug Administration pregnancy category B.1

TOLERABILITY

Sedation is common with guanfacine treatment and can be severe in a small number of children. Somnolence and fatigue are also common, affecting 9 to 40 percent of children. 2,3 These effects generally occur within two to three weeks of starting therapy and tend to decrease over time; most patients report not having these effects by the end of the eight- to nine-week treatment period.2–4 The dosage should be slowly titrated up to avoid these adverse effects. In clinical trials, 12 percent of patients taking guanfacine discontinued therapy, compared with 4 percent of those taking placebo. The most common reasons for discontinuation were somnolence and sedation.1 Patients on long-term (i.e., 12 to 24 months) guanfacine therapy reported adverse effects similar to those seen in shortterm studies, with somnolence, sedation, and fatigue being the most common. As with short-term therapy, the adverse effects from long-term therapy generally decrease over time.2–6

EFFECTIVENESS

Guanfacine is effective in the short-term (i.e., eight to nine weeks) treatment of ADHD. Dosages of 1 to 4 mg per day decrease scores on the ADHD Rating Scale-IV by an average of 17 to 21 points, compared with a decrease of 9 to 12 points with placebo.2,3 When adjusted for age, the changes in ADHD Rating Scale-IV scores were not statistically significant compared with the placebo group in patients 13 to 17 years of age, but were for patients six to 12 years of age.2,3 Therefore, effectiveness in children 13 to 17 years of age is questionable. Both physician ratings and parent assessments expressed marked improvement in more children receiving guanfacine compared with those receiving placebo. About twice as many children receiving guanfacine had statistically significant improvement on the Clinical Global Impressions Improvement scale. Similarly, 36 to 62 percent of patients taking guanfacine had statistically significant improvement on the Parent Global Assessment scale compared with 30 percent of those taking placebo.2

The duration of action of guanfacine, at least at lower dosages, is no more than eight hours, and higher dosages may be needed to produce sustained effectiveness.2,3 Guanfacine has not been compared directly with other ADHD medications, including psychostimulant medications, clonidine, and atomoxetine (Strattera).

PRICE

Guanfacine (2 to 3 mg per day) costs approximately $156 per month. Atomoxetine, the other noncontrolled substance used to treat ADHD, is similarly priced at approximately $203 per month for a dosage of 80 mg per day. A typical stimulant medication, methylphenidate extended-release (Ritalin SR; 20 mg per day), costs approximately $86 per month.

SIMPLICITY

The starting dosage of guanfacine is 1 mg per day. The dosage can be titrated up in increments of 1 mg per week to a maximum dosage of 4 mg per day. Tablets should not be chewed or crushed. Guanfacine should be given on a daily basis for the entire week, not just on school days, to avoid issues with returning or worsening somnolence and potential, but rare, increases in blood pressure. Patients who miss two or more consecutive doses may need to restart therapy at 1 mg per day and then titrate the dosage up based on patient tolerability. To discontinue guanfacine, the dosage should be tapered by 1 mg every three to seven days.1

Guanfacine

Before taking guanfacine,

  • tell your doctor and pharmacist if you are allergic to guanfacine, any other medications, or any of the ingredients in guanfacine tablets or extended-release tablets. Ask your pharmacist for a list of the ingredients.
  • you should know that guanfacine is the active ingredient in guanfacine tablets and guanfacine extended-release tablets. Do not take both of these products at the same time.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: antidepressants; antihistamines; barbiturates such as phenobarbital (Luminal); carbamazepine (Carbatrol, Epitol, Equetro, Tegretol); clarithromycin (Biaxin, in PrevPac); indinavir (Crixivan); itraconazole (Onmel, Sporanox); ketoconazole (Nizoral); medications for anxiety, high blood pressure, mental illness, nausea, or seizures; nefazodone; nelfinavir (Viracept); phenytoin (Dilantin, Phenytek); pioglitazone (Actos, in Actoplus Met, in Duetact, in Oseni); rifabutin (Mycobutin); rifampin (Rifadin, in Rifamate, in Rifater, Rimactane); ritonavir (Norvir, in Kaletra); sedatives; sleeping pills; tranquilizers; and valproic acid (Depakene). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor what herbal products you are taking, especially St. John’s wort.
  • tell your doctor if you have ever fainted, or if you have recently had a heart attack; and if you have or have ever had a stroke; low blood pressure; a slow heart rate; bipolar disorder (manic depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods); or heart, kidney or liver disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking guanfacine, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking guanfacine.
  • you should know that guanfacine may make you drowsy or dizzy. 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 guanfacine. Alcohol can make the side effects from guanfacine worse.
  • you should know that guanfacine may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking guanfacine. 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 you may faint if you become dehydrated or overheated during your treatment with guanfacine. Be sure to drink plenty of liquids and stay cool while you are taking this medication.
  • you should know that guanfacine should be used as part of a total treatment program for ADHD, which may include counseling and special education. Make sure to follow all of your doctor’s and/or therapist’s instructions.
  • talk to your doctor about the risks and benefits of taking guanfacine if you are 65 years of age or older. Older adults should not usually take guanfacine because it is not as safe or effective as other medications that can be used to treat the same condition.

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