When to take unisom?

Is it safe to take Unisom or other over-the-counter sleeping pills long-term?

If underlying conditions or medications have been ruled out as the cause, talk to your doctor about trying cognitive behavioral therapy. Studies have found it helps 70 percent to 80 percent of people with chronic insomnia—and several studies have found it to be more effective than sleeping pills alone. In other studies, a combination of the two has helped most.

One advantage of trying behavioral therapy is that there is no risk of medication side effects, plus you could experience long-lasting benefits, something pills won’t deliver since they only work when you take them.

If you and your doctor decide a prescription sleep medication is an option for you, consider zolpidem, the generic version of Ambien. It’s a Consumer Reports Best Buy drug. Our analysis found it’s the best initial prescription option for many people because of its efficacy, relative safety, and low price. But zolpidem and other prescription insomnia pills can still cause many of the same side effects as over-the-counter products, so be careful to use as low a dose as possible to help reduce the risk. And don’t take any sleeping pills for more than seven nights.

How Long Does Unisom Stay In Your System?

Unisom (doxylamine succinate) is a first-generation antihistamine available as an over-the-counter medication in the United States. It is commonly used as a sleep aid (to combat insomnia), an antiallergenic (to reduce severe allergies), and sometimes to treat symptoms of the common cold. The pharmacological ingredient within Unisom, known as “doxylamine,” functions predominantly via antagonism of H1 histamine receptors, thereby attenuating histaminergic neurotransmission.

Doxylamine exhibits sedative properties superior to pharmaceutical-grade hypnotics such as phenobarbital, and is clearly among the most potent over-the-counter hypnotic agents on the market. In addition to its effect as an antihistamine and sedative, Unisom has notable anticholinergic properties. The anticholinergic properties may lead some users to experience adverse reactions such as: ataxia, brain fog, dry mouth, memory impairment, and prolonged drowsiness.

Though Unisom is clearly an effective sleep-aid, sometimes the costs (in terms of adverse effects) outweigh the benefits of sleep induction. Furthermore, many users of Unisom may be concerned that the drug may impair their performance at work, school, increase their likelihood of a motor vehicle accident, or perhaps cause dementia. As a result, many frequent users of this over-the-counter sleep aid will cease usage, only to wonder how long it stays in their system.

How long does Unisom stay in your system?

If you were a regular user of Unisom and stop taking it abruptly, it is possible that you may experience some Unisom withdrawal symptoms. It is also possible that you may continue to experience side effects associated with the drug, leaving you to question whether any of the chemical is still in your system. To determine how long Unisom is likely to remain in systemic circulation, we must analyze the half-life of its active ingredient “doxylamine succinate.”

Doxylamine succinate is reported to have an elimination half-life of approximately 10 hours in humans. Based on this information, we know that 50% of your final Unisom dosage should be out of your system in less than half-a-day. However, for complete 100% systemic elimination, it’ll likely take an average of 2.29 days for healthy adults.

Keep in mind that this estimation of elimination is aimed at users of Unisom in the United States. Outside of the United States, Unisom formulations contain the active ingredient “diphenhydramine hydrochloride,” the primary ingredient in Benadryl. To learn how long Unisom sold outside of the United States stays in your system, simply reference the article, “How long does Benadryl stay in your system?”

  • Source: https://pubchem.ncbi.nlm.nih.gov/compound/doxylamine
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/4056080

Variables that influence how long Unisom stays in your system

Though we can estimate that Unisom manufactured in the United States is likely to remain in a user’s system for approximately 2.29 days after cessation, there is often interindividual variance in elimination speed. In other words, not everyone will eliminate the drug in precisely 2.29 days; some will be faster or slower than average in regards to excretion. The variance in interindividual excretion speed is a byproduct of variables such as: the specific person taking Unisom, dosage, frequency of administration, and whether other drugs were simultaneously administered.

  1. Individual factors

Consider the idea that two individuals could simultaneously ingest a single identical (6.25 mg) dosage of Unisom. Though each user may eliminate the drug in less than 3 days, one user may eliminate the drug in exactly 50 hours, yet the other person may eliminate it from his/her system in 60 hours. Assuming equal-strength single doses were ingested simultaneously, the 10 hour difference in elimination speed can usually be explained by individual factors.

Age + Sex: One study compared the pharmacokinetics of doxylamine succinate among young adults (ages 20 to 43) to that among elderly (ages 60 to 87). Single oral doses of 25 mg were administered to each of the participants and researchers took note of pharmacokinetic differences. It appeared as though elderly men exhibited reduced doxylamine clearance and a prolonged half-life compared to young adults and elderly women.

The half-life of doxylamine succinate among elderly men increased by approximately 5.3 hours to 15.5 hours. This suggests that elderly men may take 3.55 days to eliminate the drug from their system, compared to less than 2.5 days for elderly women and young adults. Though the exact reason for which Unisom is likely to remain in the system of elderly men for a longer duration isn’t well known, it is speculatively associated with reduced efficiency of transformation via oxidation.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/2743704

Body Fat %: It is apparent that the doxylamine succinate within Unisom is highly lipophilic, meaning it is soluble in fat. For this reason, it may be necessary to consider a Unisom user’s body fat percentage when estimating how long the doxylamine succinate is likely to remain in his/her system after discontinuation. Among users with a high percentage of body fat, an increased propensity of doxylamine accumulation is likely because they have a greater number of fat stores.

Greater accumulation of the drug within fat stores means that it will be eliminated from a user’s system at a slower rate. On the other hand, a person with a low percentage of body fat will not have as many fat stores to harbor the same quantity of doxylamine after ingestion, meaning it is likely to get eliminated at a faster rate. Furthermore, it is necessary to also consider that individuals with a high percentage of body fat may affect disposition of Unisom, perhaps also contributing to a prolonged elimination.

  • Source: http://www.medsafe.govt.nz/profs/datasheet/p/PharmacistsOwnPainReliefPlustab.pdf

Genetics: When contemplating how long doxylamine from Unisom is likely to stay in your system, it helps to know your genetics. Though the specific metabolism pathways for doxylamine succinate aren’t fully elucidated, it is believed to undergo hepatic metabolism via CYP450 (cytochrome P450) enzymes. Some have gone as far as to hypothesize that CYP2D6 isoenzymes have the highest affinity for doxylamine succinate metabolism.

Since many CYP450 genes are subject to polymorphisms that in turn affect enzymatic function, your genes may affect how quickly Unisom is metabolized and cleared from your system. Since CYP2D6 is highly polymorphic, and likely to facilitate most of Unisom metabolism, it is possible that you (as a user) may exhibit poor metabolism based on CYP2D6 allelic expression.

Assuming you are in fact a poor metabolizer of doxylamine as a result of alleles associated with the CYP2D6 gene, the half-life of doxylamine may increase significantly. On the other hand, if you exhibit optimal expression of CYP2D6 alleles as to facilitate peak CYP2D6 isoenzyme function, you may metabolize doxylamine much quicker and eliminate it faster from systemic circulation. Though the differences in half-lives of Unisom aren’t fully understood based on CYP2D6 alleles, they likely affect how long it stays in your system compared to the mean elimination time.

Hepatic function: The doxylamine succinate within Unisom is known to function as an H1 receptor antagonist. Some reports suggest that H1 receptor antagonists are eliminated at a slower rate among those with severe hepatic impairment (e.g. cirrhosis). Therefore if you have a severe form of liver disease, expect the elimination half-life of doxylamine succinate to increase compared to those with normative hepatic function.

Prolonged elimination likely occurs among those with hepatic impairment as a result of decreased enzymatic function. When liver function is impaired, the function of hepatic enzymes decreases, leading to higher plasma concentrations of drugs and poorer metabolism. Users of Unisom should expect altered elimination speed reflective of the extent to which they are hepatically impaired.

Metabolic rate: A person’s BMR (basal metabolic rate) is thought to affect how long certain drugs remain in systemic circulation. Individuals with extremely high BMRs (such as evidenced in cases of hyperthyroidism) are believed to metabolize and eliminate drugs at a faster rate than those with extremely low BMRs (as evidenced by cases of hypothyroidism). Assuming you have neither hyper- nor hypo-thyroidism, your metabolic rate may still differ slightly from that of another Unisom user’s.

Though the effect of BMR on elimination of Unisom may not be regarded as clinically significant in most cases, it is likely to affect speed to a minor (perhaps negligible) extent. If you have a higher BMR than average, you may also be likely to eliminate Unisom faster than average. However, BMR in and of itself is likely not a major determinant of Unisom’s elimination rate – unless an individual is extremely high or low BMR.

Other drugs: It is necessary to consider that taking other drugs may affect how long Unisom stays in your system. Though doxylamine succinate may not undergo extensive hepatic metabolism like many other drugs, at least 40% of an ingested dose is hepatically metabolized. Should a co-administered drug interfere with this hepatic metabolism, plasma concentrations of the parent compound may increase, and elimination may be extended.

Though we cannot pinpoint the specific enzymes responsible for the majority of Unisom’s metabolism, some speculate that CYP2D6 plays a prominent role. If CYP2D6 isoenzymes are the major determinant of Unisom metabolism, any co-administered agent (drug or supplement) that interferes with CYP2D6 function would likely prolong elimination of Unisom, whereas co-administered agents that bolster CYP2D6 function may reduce elimination time.

Renal function: Most orally ingested drugs undergo hepatic metabolism are distributed, and are then eliminated via the urine by way of the kidneys. Since the kidneys play a role in the elimination of Unisom, the degree to which they are functioning properly or improperly may influence how long the drug stays in a person’s system after discontinuation. Individuals with renal impairment may accumulate more of the Unisom in their kidneys and excrete it with reduced efficiency than someone with normative renal function.

The extent to which renal impairment will affect Unisom’s elimination half-life is likely reflective upon the severity of the actual impairment. Severe forms of impairment likely reduce clearance speed and efficiency, perhaps allowing greater amounts of Unisom to be reabsorbed prior to complete elimination.

  1. Dosage (6.25 mg to 25 mg)

The amount of Unisom (doxylamine succinate) an individual ingests is likely to dictate how long it stays in their system (to a certain extent). When considering the drug’s half-life of approximately 10 hours, it is apparent that a person taking a single dose of 20 mg would have less of the drug in his/her system than a user taking just 10 mg. After 20 hours post-ingestion, the 20 mg user would still have 10 mg lingering in his/her system, whereas the 10 mg user would only have 5 mg.

Though both would be likely to eliminate the drug in under 3 days, dosage may slightly affect how long the drug stays in systemic circulation. Among high dose users, a greater quantity of the drug is ingested, and as a result, it forces hepatic CYP450 enzymes in the liver to work harder for its metabolism. Up to a certain threshold, these enzymes can tolerate the extra quantity, but once that threshold is exceeded, their efficiency plummets; meaning poorer metabolism of Unisom.

It is this reason that we’d expect the half-life of Unisom to be much longer among someone who had taken a supratherapeutic dose (or deliberately overdosed) than someone taking the drug within normal dosage guidelines. Furthermore, we could expect a greater quantity of Unisom to accumulate in fat stores throughout the body, and an increasing number of metabolites to form. This also means that elimination efficiency will be prolonged because there’s a greater amount of the drug that necessitates elimination, taxing the kidneys to a greater extent than they would under normative circumstances (e.g. taking a standard dose).

Among a low dose user, the liver isn’t taxed to as great of an extent, allowing it to efficiently metabolize doxylamine succinate. The body isn’t overloaded with distribution of large quantities of a highly lipophilic compound, and as a result, less accumulation is likely. Finally, low dose users have less of the drug to eliminate (because they ingested less), so the body will clear it from the system with greater efficiency.

  1. Frequency of administration

How often a person administers Unisom could also affect the duration it stays in their system after discontinuation. Research shows that multi-dose users of Unisom are likely to retain the drug for a longer duration after discontinuation than single-dose users. There are a number of reasons as to why multi-dose users retain the drug for a longer duration after cessation including: greater doses ingested per day, heightened accumulation of doxylamine succinate (and metabolites), and attainment of steady state concentrations.

Though multi-dose users may take “less” Unisom on a per dose basis than a single-dose user, the multi-dose users tend to ingest a greater amount of the drug per 24 hours than a single-dose user. A single dose user may take 20 mg once before bed, while a multi-dose user may take 15 mg twice throughout the day for a total of 30 mg ingested; 10 mg more than the single-dose user. As was already mentioned, increased doses, especially over a short-term such as 1 day, are likely to extend elimination half-life.

Research also shows that multi-dose administration of Unisom results in heightened accumulation of the drug. In other words, plasma concentrations are elevated and fat stores retain a greater amount of Unisom in multi-dose users, leading to an increased elimination half-life. As a general rule of thumb, realize that the greater the frequency at which you ingest Unisom, the more likely it’ll stay in your system for a longer duration after cessation.

Unisom: Absorption, Metabolism, Excretion (Details)

Following oral administration of Unisom, its active ingredient “doxylamine succinate” is readily absorbed by the gastrointestinal (GI) tract, primarily within the jejunum. After a single 25 mg dose is administered to healthy adults, peak plasma concentrations (of approximately 100 ng/ml) are attained in an estimated 2.4 hours post-ingestion (usually between 2 and 3 hours). The distribution volume of doxylamine succinate is reportedly 2.5 L/kg.

The drug acts as an antihistamine with hypnotic, anticholinergic, and antimuscarinic properties. The effect of doxylamine succinate is believed to last between 6 and 8 hours, with plasma concentrations declining to 28 ng/ml after 24 hours. By 36 hours post-ingestion, plasma concentrations will have declined to just 10 ng/ml.

It is believed that doxylamine succinate is subject to hepatic metabolism via various CYP450 enzymes. These CYP450 enzymes facilitate N-demethylation, N-oxidation, hydroxylation, N-acetylation, and ether cleavage. In the process, the two most notable metabolites formed include: nordoxylamine and dinordoxylamine.

The elimination half-life of doxylamine succinate is approximately 10.1 hours, indicating that it’ll be cleared from systemic circulation (likely along with its metabolites) in approximately 2.29 days after discontinuation. The metabolites are then processed by the kidneys and eliminated via urine. Urinary excretion consists of: 60% unchanged doxylamine succinate with the remaining 40% as nordoxylamine and dinordoxylamine metabolites.

Tips to clear Unisom from your system

If you are concerned that Unisom is still in your body after discontinuation, there are some steps you can actively take to ensure that it gets fully eliminated in a timely manner. Keep in mind that the safety and alleged efficacy of these tips should be discussed with a medical professional prior to implementation. That said, below are some strategies that could be implemented for a rapid detox.

  1. Burn fat: We all know that exercise can be a great way to detoxify from drug usage. Unisom is a lipophilic drug and may accumulate in adipose tissue or fat stores throughout the body. Burning some of this excess fat via exercise may force Unisom to be get cleared from the system faster than it usually would – especially among those with an already-high percentage of body fat.
  2. Calcium-D-Glucarate: It is known that Unisom is primarily eliminated via urine in unchanged form. The kidneys coordinate urinary excretion of drugs, but may be taxed with other toxins and potentially from large doses of Unisom (if you were a heavy user). Calcium-d-glucarate is a supplement that acts as a beta-glucuronidase inhibitor, essentially clearing detox pathways and allowing for improved elimination of toxins (and possibly drugs like Unisom).
  3. Activated charcoal: An effective way to detoxify the gastrointestinal tract and liver is via supplementation with activated charcoal. If any unmetabolized Unisom is still in your body, activated charcoal will bind to it through “adsorption,” and essentially chauffer it to be excreted as rapidly as possible. Furthermore, activated charcoal binds to endotoxins within the gut that may have been generated as a result of Unisom ingestion.
  4. Urinary pH: Although the acid lability of Unisom isn’t understood, it is possible that the drug is acid labile. If it is acid labile, increasing the acidity of your urine via modification of dietary intake may be an effective method for expediting Unisom’s excretion. Highly acidic urine may destroy some of the metabolites and/or ensure that they are eliminated with efficiency, whereas alkaline urine may promote reabsorption and redistribution, thereby prolonging elimination.

How long has Unisom stayed in your system after stopping?

If you’ve recently stopped taking Unisom, share a comment regarding how long you believe it stayed in your system after your final dose. Discuss whether you believe the Unisom stayed in your system for longer than average (2.29 days) or for a shorter duration than average. To help support your hypothesis, mention factors such as whether you were a single-dose or multi-dose user, the dosage you were taking, as well as whether you were taking other drugs that may have interfered with its metabolism or elimination.

Realize that the majority of healthy Unisom users should eliminate the drug from their systems within 3 days of discontinuation. Keep in mind that many people mistakenly believe that the drug is still in their “system” for longer than several days after stopping because they still experience side effects. In most cases, these side effects are not from a lingering circulation of Unisom, rather they are from lingering neurophysiologic changes that occurred whilst Unisom was still in the system.

Over-the-counter sleep aids: The research on their effectiveness is limited, experts say

Every morning I am greeted by Facebook friends complaining of sleepless nights or awakenings. I know the feeling — as do many other Americans.

In a 2005 survey of 1,506 Americans by the National Sleep Foundation, 54 percent reported at least one symptom of insomnia — difficulty falling asleep, waking a lot during the night, waking up too early or waking up feeling unrefreshed — at least a few nights a week over the previous year. Thirty-three percent said they had experienced symptoms almost every night.

If insomnia visited me that often, I’d be tempted to pick up something at the pharmacy — something easy, something safe, something that didn’t involve making a doctor’s appointment. Indeed, 10 to 20 percent of Americans take over-the-counter sleep aids each year, according to the American Academy of Sleep Medicine.

The way they’re marketed, over-the-counter sleep aids sound very appealing: The new product ZzzQuil (yes, from the maker of NyQuil) promises “a beautiful night’s sleep;” an ad says you’ll “fall asleep faster and stay asleep longer” after using Unisom. Companies marketing the herb valerian root and the hormone melatonin as over-the-counter sleep aids make similar claims.

But what’s the evidence that supports these claims? “It’s quite lean,” says Andrew Krystal, who directs the sleep research program at Duke University.

Another reason why sleep aids don’t work: Insomnia is not just a nighttime phenomenon. (iStockphoto)

Over-the-counter sleep aids work differently from prescription drugs for insomnia. Most are simply antihistamines in sheep’s clothing. (Yes, that’s a joke.) The majority of them — ZzzQuil, TylenolPM and Unisom SleepGels — contain diphenhydramine as the active ingredient, the same compound in Benadryl. (Unisom SleepTabs use doxylamine, another antihistamine.)

The clinical studies testing diphenhydramine for insomnia are minimal, Krystal says: There have been only two, which together involved 204 people. “That’s it. That’s all we have,” he says. (Other studies have looked at daytime sleepiness with the drug.)

The studies looked at people with primary insomnia — meaning that their sleep problems were not the result of other medical issues such as depression, anxiety or pain.

The first study included a comparison of the effects of diphenhydramine (50 milligrams, a typical OTC dose) with those of a placebo in 20 elderly people with insomnia. The participants reported slightly fewer nighttime awakenings with diphenhydramine than with the placebo, but no difference in how long they took to fall asleep, how well they slept or how long they slept.

The second study tested 25-milligram doses of diphenhydramine against a placebo and an herbal preparation of valerian and hops in 184 adults with mild insomnia. Compared to a placebo, diphenhydramine improved sleep efficiency (the percentage of time in bed spent sleeping) based on participants’ feedback but not on automated readings of brain, eye and muscle activity. Neither did it affect sleep onset or total sleep time.

What these studies did find with diphenhydramine was side effects, including dry mouth, dizziness and headache. Other side effects that can occur with diphenhydramine are constipation and urinary retention, Krystal says.

The valerian-hops combination helped, to some degree: People who took that mixture reported that it took slightly less time to fall asleep and that their insomnia was less severe.

The problem with valerian root is that there’s so much variety in the preparations, says Vivek Jain, who directs the Center for Sleep Disorders at George Washington University Hospital. You can’t be certain how much active ingredient you’re getting, he says, and because these products are regulated as supplements rather than drugs, their composition can vary from one maker to the next.

Krystal concurs. “You never know what you’re getting. It’s an extract from a root. . . . No two batches will be the same.”

The bottom line is that the evidence has not shown more than modest effects of valerian, Krystal says.

What about melatonin? Jain says there is some evidence that it helps people fall asleep more quickly. A 2011 study of prolonged-release melatonin found that insomnia patients age 55 to 80 fell asleep 15 minutes sooner than with placebo, on average, but younger patients did not benefit.

Krystal says that melatonin is helpful for shifting one’s day-night cycle, for people changing time zones or work shifts and for helping night owls go to sleep at what is for them an unnaturally early time.

There’s a larger reason why sleep aids don’t work, Jain says, and that’s because insomnia is not just a nighttime phenomenon. “It’s a 24-hour problem,” he says. Our wakeful state is akin to second or third gear in a car with a five-gear transmission. At night we drop into first gear or neutral.

“In insomnia, these gear shifts get unstable,” Jain says. Insomniacs spend their days in higher gears than most people, and they have trouble downshifting at night. “Patients don’t recognize the daytime problem. They just want to sleep more and more,” he says.

When considering sleep aids, he cites the lack of benefit and the risk of side effects and says, “There’s no good reason to take these. Ever.”

If you are going to use them, he says, “use them intermittently — not every night.”


How does this medication work? What will it do for me?

Diphenhydramine belongs to a group of medications known as antihistamines. Antihistamines are used to treat symptoms caused by allergies, including itchy and watery eyes, sneezing, runny nose, and skin irritation. Diphenhydramine also causes drowsiness, and can be used by adults and children 12 years of age and older who occasionally have trouble sleeping (insomnia). The effects of diphenhydramine can last for up to 6 hours.

If you have trouble sleeping, do not take this medication for more than a few nights in a row. Talk to your doctor about other treatment options suitable for you if you have chronic (long-term) insomnia that persists for more than a few nights at a time.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

25 mg SleepGels
Each capsule contains 25 mg of diphenhydramine HCl. Nonmedicinal ingredients: gelatin, glycerin, polyethylene glycol, purified water, sorbitol, soy lecithin, and titanium dioxide.

50 mg
Each tablet contains 50 mg of diphenhydramine HCl. Nonmedicinal ingredients: calcium phosphate, cellulose, FD&C Blue No. 1 Aluminum Lake, hypromellose, magnesium stearate, polyethylene glycol, and sodium starch glycolate.

50 mg SleepGels
Each capsule contains 50 mg of diphenhydramine HCl. Nonmedicinal ingredients: FD&C Blue No. 1 Aluminum Lake, gelatin, glycerin, Opacode solution, polyethylene glycol, sorbitol, and water.

How should I use this medication?

The usual dose for adults and children 12 years of age and older to help with sleep is 25 mg to 50 mg taken by mouth at bedtime. Some people may only need to take 25 mg at bedtime if they are drowsy in the morning (e.g., they find it interferes with their daily activities) after taking the 50 mg dose.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

Store this medication at room temperature and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to diphenhydramine or any ingredients of the medication
  • have an enlarged prostate
  • have an obstructed bladder
  • have asthma or chronic lung disease
  • have certain stomach conditions (e.g., stenosing peptic ulcer or pyloroduodenal obstruction)
  • have narrow-angle glaucoma
  • have taken an antidepressant medication known as a MAO inhibitor (e.g., phenelzine, tranylcypromine, linezolid) within the past 2 weeks

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • chest congestion
  • constipation
  • dizziness
  • drowsiness
  • dry mouth, nose, and throat
  • headache
  • inability to concentrate
  • increased perspiration
  • nausea or vomiting
  • restlessness
  • upset stomach

Although most of the side effects listed below don’t happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • decreased muscle coordination
  • difficulty in passing urine
  • excitation (especially in children)
  • insomnia
  • muscle weakness
  • nervousness
  • rapid heart rate
  • vision problems

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • chest tightness
  • skin rash or hives
  • wheezing

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Bladder or urinary problems: Diphenhydramine can worsen symptoms of bladder problems. If you have a history of bladder problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Drowsiness/reduced alertness: Avoid driving or operating machinery until you have determined that you do not become drowsy during the day or experience impaired mental or physical abilities while taking this medication. Alcohol, sedatives, and pain medications can increase the side effects (e.g., drowsiness, inability to concentrate) of this medication. Do not undertake any activities that require alertness until you know how this medication affects you.

High blood pressure: If you have high blood pressure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Lung problems: This medication can make breathing problems worse. If you have lung problems such as asthma or chronic obstructive pulmonary disease (COPD), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Medical conditions: For some people, insomnia is caused by other medical conditions. If you have trouble sleeping for longer than 2 weeks, contact your doctor before taking this medication.

Thyroid disease: People with thyroid disease should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication may pass into breast milk. If you are a breast-feeding mother and are taking diphenhydramine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: Diphenhydramine is not recommended for use as a sleep aid for children less than 12 years of age.

Seniors: Seniors may experience more side effects with this medication. Talk to your doctor before taking this medication.

What other drugs could interact with this medication?

There may be an interaction between diphenhydramine and any of the following:

  • aclidinium
  • alcohol
  • alfuzosin
  • amiodarone
  • amphetamines (e.g., dextroamphetamine, lisdexamphetamine)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • atomoxetine
  • atropine
  • azelastine
  • barbiturates (e.g., butalbital, pentobarbital, phenobarbital)
  • belladonna
  • benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
  • benztropine
  • botulinum toxins
  • brimonidine
  • buprenorphine
  • buspirone
  • captopril
  • carvedilol
  • chloral hydrate
  • chloroquine
  • cyclobenzaprine
  • degarelix
  • dextromethorphan
  • disopyramide
  • dofetilide
  • domperidone
  • donepezil
  • doxorubicin
  • dronabinol
  • dronedarone
  • efavirenz
  • flavoxate
  • flecainide
  • galantamine
  • general anesthetics (medications used to put people to sleep before surgery)
  • glycopyrrolate
  • hyaluronidase
  • ipratropium
  • ketotifen
  • lopinavir
  • macrolide antibiotics (e.g., clarithromycin, erythromycin)
  • magnesium sulfate
  • methadone
  • methamphetamine
  • metoprolol
  • mexiletine
  • mifepristone
  • minocycline
  • mirabegron
  • mirtazapine
  • muscle relaxants (e.g., baclofen, cyclobenzaprine, methocarbamol, orphenadrine)
  • nabilone
  • narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone)
  • nefazodone
  • olopatadine
  • other antihistamines (e.g,. cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
  • oxybutynin
  • perampanel
  • pimozide
  • potassium chloride
  • pramipexole
  • procainamide
  • quinidine
  • quinine
  • quinolone antibiotics (e.g., ciprofloxacin, ofloxacin, sparfloxacin)
  • rilpivirine
  • rivastigmine
  • ropinirole
  • rotigotine
  • rufinamide
  • scopolamine
  • secretin
  • seizure medications (e.g., clobazam, ethosuximide, felbamate, levetiracetam, phenobarbital, phenytoin, primidone, topiramate, valproic acid, zonisamide)
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, duloxetine, fluoxetine, paroxetine, sertraline)
  • serotonin agonists (e.g., dolasetron, granisetron, ondansetron)
  • sotalol
  • tamoxifen
  • tapentadol
  • thalidomide
  • timolol
  • tiotropium
  • tolterodine
  • topiramate
  • tramadol
  • tranylcypromine
  • trazodone
  • tricyclic antidepressants (e.g., amitriptyline, desipramine, imipramine, nortriptyline)
  • tyrosine kinase inhbitors (e.g., lapatinib, pazopanib, sunitinib)
  • umeclidinium
  • venlafaxine
  • voriconazole
  • zolpidem
  • zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

All material copyright MediResource Inc. 1996 – 2020. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/drug/getdrug/Unisom

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