Doxylamine succinate drug interactions

Doxylamine Drug Interactions

A total of 285 drugs are known to interact with doxylamine.

  • 15 major drug interactions
  • 269 moderate drug interactions
  • 1 minor drug interaction

Show all medications in the database that may interact with doxylamine.

Check for interactions

Type in a drug name to check for interactions with doxylamine.

Most frequently checked interactions

View interaction reports for doxylamine and the medicines listed below.

  • Adderall (amphetamine / dextroamphetamine)
  • Ambien (zolpidem)
  • Aspirin Low Strength (aspirin)
  • azithromycin
  • Benadryl (diphenhydramine)
  • Claritin (loratadine)
  • codeine
  • CoQ10 (ubiquinone)
  • Cymbalta (duloxetine)
  • Dextromethorphan HBr Adult Formula (dextromethorphan)
  • diphenhydramine
  • Fish Oil (omega-3 polyunsaturated fatty acids)
  • Flonase (fluticasone nasal)
  • guaifenesin
  • ibuprofen
  • Lexapro (escitalopram)
  • Lyrica (pregabalin)
  • melatonin
  • mirtazapine
  • naproxen
  • Nexium (esomeprazole)
  • Paracetamol (acetaminophen)
  • paroxetine
  • prednisone
  • pseudoephedrine
  • pyridoxine
  • sertraline
  • tramadol
  • Tylenol (acetaminophen)
  • Vitamin B12 (cyanocobalamin)
  • Vitamin B6 (pyridoxine)
  • Vitamin C (ascorbic acid)
  • Vitamin D3 (cholecalciferol)
  • Xanax (alprazolam)
  • Zoloft (sertraline)
  • zolpidem
  • Zyrtec (cetirizine)

Doxylamine alcohol/food interactions

There is 1 alcohol/food interaction with doxylamine

Doxylamine disease interactions

There are 8 disease interactions with doxylamine which include:

  • depression
  • anticholinergic effects
  • asthma/COPD
  • cardiovascular
  • renal/liver disease
  • glaucoma
  • liver disease
  • resp depression

More about doxylamine

  • Side Effects
  • During Pregnancy
  • Dosage Information
  • Drug Images
  • Support Group
  • Pricing & Coupons
  • En Español
  • 163 Reviews
  • Drug class: miscellaneous anxiolytics, sedatives and hypnotics

Related treatment guides

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  • Allergic Rhinitis
  • Allergies
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  • … +3 more

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.


Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.


Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.


Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.


No interaction information available.

Further information

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

Medical Disclaimer

I took the Kirkland Signature sleep aid every night for the last week to see if it would help with both my insomnia and dust mite allergy.

The main active ingredient is the anti-histamine Doxylamine Succinate, which is also used in other brands of over the counter sleep aids. Kirkland Signature is a private brand of Costco, and their sleep aid is widely available in the United States.

Interestingly, it has identical ingredients to Unisom SleepTabs. Perhaps that’s why they felt the need to state on the label that it’s not made by the same company.

In this Kirkland sleep aid review, I’ll be describing my experience taking it, which should be similar to when I tried Unisom – in theory. And I’ll also cover some of the warnings and side effects.

My experience

The first night

My first impression was that the Kirkland sleep aid is, like Unisom, very small and easy to swallow.

The instructions tell you to take one tablet 30 minutes before going to bed. So I took one just as I got into bed and then read for a while. I always like to read after testing a sleep aid to see if there are obvious signs of sedation.

And since I was staying with a friend again, who has a notoriously dusty house (sorry if you’re reading this!), I wanted to see if it would stop my sniffling.

After around 30-40 minutes of reading, I did indeed feel that my nose was less irritated. And I also switched the light out to go to sleep.

I then woke up around 6.5 hours later, which is a good result for me. I often wake in the night at least a couple of times, and I average 6 to 7 hours’ sleep on a good night.

I felt a little groggy on first waking up, but it quickly cleared up after a shower and coffee. This was again very similar to the first time I took Unisom.

The following nights

As I was expecting, the pattern for the rest of the week when taking the Kirkland sleep aid was quite similar to the Unisom – though not exactly the same, just to be clear.

One thing is for sure, it definitely helped me in my eternal battle with the invisible hordes of dust mite.

As for sleep, I slept pretty well for 5 of the remaining 6 nights, though did have sporadic wakings. On the fifth night, I really didn’t feel any drowsiness and had a restless night. Maybe I slept well again the final night through tiredness – it’s impossible to say.

Increasing morning grogginess

The groggy next-day effect also increased throughout the week, as it did with all the anti-histamine sleep aids I’ve tried in the past. This seems inevitable if you continue taking them, which is why I rarely take them for more than a few nights at a time.

So by morning 4, it was taking a couple of hours to transition from what I’d put as 70% alertness on waking to 100% alert.

Still, it’s not a bad trade-off for what felt like a reasonably good night’s sleep, and distinctly better than the lack of alertness I feel after a night of endless tossing and turning.

So all in all, I felt like it did its job of helping me get off to sleep when I was having trouble sleeping in the previous days. And the side effects were tolerable, though I wouldn’t want to push it and keep taking the sleep aid for longer.

What evidence is there that the Kirkland sleep aid works?

As with most over the counter sleep aids, the manufacturer doesn’t need to conduct clinical trials to sell it. All they need to do is adhere to the general standards in the country where supplements and ingredients of this type are concerned.

So, it’s probably more useful to see what evidence there is that the active ingredient works as a sedative. And for that, there’s no shortage of medical sites that talk about it causing drowsiness. The FDA even approved Unisom for use as a sleep aid.

A team of researchers in 2012 pointed out that it’s been an established drug for more than 50 years:

Currently, doxylamine medicinal products have been authorized for more than 50 years, with an appropriate extent of use, for symptomatic treatment of occasional insomnia, making doxylamine a drug with a well established use.

However, a team of researchers in 2015, which examined previous research studies into over the counter sleep aids, had this to say:

Currently available literature suggests that commonly used OTC sleep agents, especially antihistamines and valerian, continue to lack robust clinical evidence supporting efficacy and safety in relevant populations

So perhaps there was a placebo effect at work when I’ve taken anti-histamine sleep aids. It might also help explain why some websites with many customer reviews have a mixture of people saying sleep aids like this one either work amazingly or do nothing.


According to the patient leaflet:

Active ingredient

  • There’s one active ingredient – Doxylamine Succinate, 25 mg

Inactive ingredients

  • Dibasic calcium phosphate
  • FD&C blue no. 1 aluminum lake
  • Magnesium stearate
  • Microcrystalline cellulose
  • Sodium starch glycolate

As I mentioned earlier, these are exactly the same ingredients as Unisom SleepTabs.

Who shouldn’t take this sleep aid

The carton has the following warnings:

1. Speak to a doctor before use if you have:

  • Glaucoma
  • A breathing problem, such as asthma, emphysema or chronic bronchitis
  • Difficulty urinating because of an enlarged prostate gland

2. Ask a doctor or pharmacist if:

  • You are taking any other medication

3. When using this sleep aid:

  • Avoid alcohol
  • Only take it at bedtime

4. Stop and speak to a doctor if:

  • The sleep problem continues for two weeks

5. If pregnant or breastfeeding:

  • Speak to a health professional first

6. Keep out of reach of children

7. If you overdose, get medical help or call a poison center

If you’d like to check this and more safety information, you can see the kirkland signature factsheet on

Warnings for older adults and children

I’ve seen an increasing number of medical sites recommend that older adults, as well as children, avoid Doxylamine Succinate. For example, WebMD says:

Older adults may be more sensitive to the side effects of this drug, especially drowsiness, dizziness, low blood pressure, confusion, constipation, or trouble urinating. Drowsiness, dizziness, and confusion can increase the risk of falling.

If you’d like some in-depth information about the use of this type of sleep aid among older adults, there’s an interesting research study from 2017 which looks into the issue and explains why it’s a potential problem.

Possible side effects

Like most over the counter sleep aids, the manufacturer is not required to list every possible side effect, since it’s sold as a supplement and not a prescription drug.

So, as with Unisom, I’ve checked medical sites like Mayo Clinic, WebMD and others for the known possible side effects of the active ingredient. They are:

  • Drowsiness
  • Dry mouth, nose or throat
  • Headache
  • Constipation or difficulty urinating
  • Stomach upset
  • Memory problems
  • Dizziness
  • Blurred vision
  • Worse coordination
  • Irregular or fast heartbeat
  • Ringing in the ears
  • Mental or mood changes (e.g. confusion, irritability, hallucinations)
  • Easy bruising/bleeding

So is it safe to take?

Most drugs can cause side effects, often with scarily long lists of potential problems. But generally, Doxylamine Succinate is tolerated reasonably well by most people for short-term use.

Having said that, I do recommend talking it through with your doctor if you’re concerned. Try not to use it for more than a few nights, and if you have any side effects, stop taking it. Finally, also try to work on your sleep problems naturally.

Your experience

Have you tried Kirkland Signature sleep aid? It’s always useful for readers to know what others think. So please feel free to share your experience in the comments below.

Kirkland Sleep Aid Review – 12 Things You Need to Know

  • User Comments
  • 10 Answered Questions

Kirkland Sleep Aid is a sleeping aid created to help its users fall asleep. Kirkland Sleep Aid claims to help its users “fall asleep fast!” Kirkland is the brand made by Costco wholesale stores, and we wondered if a supplement made by a wholesale store, and not a health product company, could be safe and effective.

To find out if Kirkland Sleep Aid could really help its users fall asleep fast, our research team spent hours researching its ingredients and comparing them to scientific data. Here is what our research team discovered about Kirkland Sleep Aid.

Kirkland Sleep Aid Readers: Noom is offering our readers a 14-day trial, for a limited time. for this special offer! Overview

What Is Kirkland Sleep Aid?

Kirkland Sleep Aid is an over-the-counter sleeping aid from the wholesale company Costco. Doxylamine is the main ingredient, is a first-generation antihistamine, according to PubChem. This ingredient can be used as a sedative and in combination with other drugs, it can offer night-time allergy and cold relief. Doxylamine can be used with other analgesics like paracetamol, and it can be recommended together with vitamin B6 (Pyridoxine) to help prevent sickness in pregnant women.

Kirkland Sleep Aid Competitors

Product Rating Review
Unisom read
Zzzquil read
Noom read

×Explanation of Price

This is how much it costs to start on the respective program. We always recommend trying a product before making a large investment.

  • = Initial product cost is less than $5
  • = Initial product cost is between $6 and $50
  • = Initial product cost is between $51 and $150
  • = Initial product cost is $151 or more

The Company Behind Kirkland Sleep Aid

Kirkland Sleep Aid is a product of the Costco Wholesale Corporation. Costco is an American based, multi-national corporation and is one of the largest retailers in the world. It employs a warehouse membership club business model and boasts over 90 million members.

Costco thrives on providing great pricing through larger volume purchases with the small business and large family in mind. Providing a larger selection of organic and specialty foods than its competitors, Costco has had a meteoric rise to the top.

Kirkland is the name of Costco’s private label brand. There are Kirkland branded products in almost every department from dry goods to cleaning supplies to health supplements.

Marketing private-label goods that meet or exceed the quality of their brand name counterparts, Costco has proven to be a valuable source of products and services.

In addition to its Kirkland branded merchandise, Costco provides additional services such as auto, optical, travel, and payment processing services for business.

Scroll below for one of the best products we’ve seen over the last year.


Ingredients in Kirkland Sleep Aid

The ingredients in Kirkland Sleep Aid are:

  • Doxylamine Succinate 25mg
  • Dicalcium Phosphate
  • FD&C Blue #1 Aluminum Lake
  • Magnesium Stearate
  • Microcrystalline Cellulose
  • Sodium Starch Glycolate


How To Use Kirkland Sleep Aid?

According to the Kirkland Sleep Aid label, the user is to take one 25mg tablet 30 minutes before bed. It is suggested that the supplement is taken only once per day, but a doctor may provide different instructions.


Kirkland Sleep Aid Product Warnings

The label states that the supplement is not safe for children 12 years and younger.

The company also warns that Kirkland Sleep Aid should only be used short-term. If long-term sleeplessness occurs, it is best to seek medical attention as there could be an underlying medical problem.


Any Proof To Support Kirkland Sleep Aid Claims?

The only active ingredient in Kirkland Sleep Aid is doxylamine succinate. The antihistamine is widely utilized to treat different forms of allergies.

There is no shortage of studies on the effects of doxylamine succinate. For instance:

Based on a study published in Principles and Practice of Sleep Medicine, “Antihistamines such as diphenhydramine and doxylamine are associated with subjective drowsiness and sleepiness, leading to their widespread use as over-the-counter hypnotic agents.”

The Mayo Clinic also agrees that “Doxylamine is…a sedating antihistamine.” Sedating meaning, it causes drowsiness.

Side Effects

Potential Kirkland Sleep Aid Side Effects

With only one active ingredient, the potential for side effects is smaller. Science does claim there are a few irritations to consider.

According to the Pharmacy and Therapeutics, doxylamine is commonly used for sleep initiation and maintenance because of sedating properties.

PubMed Health shares a list of potential side effects associated with the active ingredient in Kirkland Sleep Aid. Side effects may include “allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing.”

Other rarer potential side effects include:

  • Difficulty in passing urine
  • Always feeling tired
  • Change in eyesight
  • Faster heartbeat rate
  • Feeling dizzy
  • Hard stools
  • Dry mouth

You should not take Kirkland Sleep Aid with antihistamines.

It is important to note that these are not all the side effects alone that have the possibility of occurring.

What to Do If Overdose Is Suspected?

If you think you have taken Kirkland Sleep Aid overdose other than the stipulated dosage in the Kirkland Sleep Aid doxylamine succinate 25mg, then it is necessary to call a doctor or get medical care immediately. You must be willing to report how much you have taken accurately.

Kirkland Sleep Aid Alternatives

Occasional sleeplessness is a problem that plagues most people from time to time, but there are several over the counter products available to help you fall asleep fast and stay asleep.

The following list reviews several well-known products and provides essential information. Preference to one brand over another is not the focus of this list.


Advertised as the number one pharmacist recommended sleep aid, Unisom is well known and widely available.

This non-habit forming, OTC medication is recommended for use by adults (ages 12 and up) who have trouble falling asleep.

This antihistamine product works by allowing your body to feel drowsy and groggy, which leads to sleep.

  • Active ingredient: Diphenhydramine HCL – 50 mg
  • Form: soft, liquid-filled gel capsule
  • Dosage: ages 12 and up; one capsule 30 minutes before bedtime
  • Warnings: Do not use if pregnant or breastfeeding. Do not combine with sedatives, tranquilizers, or OTC cold remedies containing antihistamine.
  • Side effect: dry mouth, confusion, dizziness


ZZZquil is formulated as an over the counter sleep aid. Available in liquid or filled capsules, ZZZquil also relies on Diphenhydramine as its active ingredient.

The product induces drowsiness which leads to sleep. The liquid form of ZZZquil does include 10% alcohol by volume, which could present a problem in individuals with a history of alcohol abuse.

  • Active ingredient: Diphenhydramine HCL- 25 mg
  • Forms: flavored liquid or liquid-filled capsule
  • Dosage: ages 12 and up; one capsule or one cupful 30 minutes before bedtime
  • Warnings: Do not use if pregnant or breastfeeding. Do not combine with sedatives, tranquilizers, or MAOI drugs. Do not use if sensitive to alcoholic products.
  • Side effects: reduced mental alertness, dizziness, residual drowsiness


Originally designed to treat allergies, colds, and itching created by sensitivity, Benadryl has been available over the counter for decades.

New uses for Benadryl include the treatment of occasional, mild sleeplessness. The active ingredient in Benadryl is Diphenhydramine HCL 25 mg, available in a small, easy to swallow tablet.

  • Active ingredient: Diphenhydramine HCL- 25 mg
  • Form: small, pink tablet
  • Dosage: ages 12 and up; one capsule as needed for itching, runny nose, allergy symptoms, sleep aid (take 30 minutes before bedtime),
  • Warnings: Do not take if pregnant or breastfeeding. Do not combine with certain over the counter cold and flu remedies.
  • Side effects: dry mouth, headache, dizziness, drowsiness, fatigue

Kino Sleep

Kino Sleep is an all-natural blend of 100% herbs and minerals. It is available in a supplement powder that is mixed with water. The company claims the product contains three particular blends of herbs to achieve different effects during sleep.

  • Sleep induction blend: This combination is labeled as calm and relaxing and guarantees to help induce sleep.
  • Restoration and recovery blend: This combination is designed to help you maintain restful, rejuvenating sleep.
  • Stimulant blockers: This ingredient removes residual caffeine from your bloodstream.
  • Dosage: 1 scoop added to water before bedtime
  • Warnings: none given
  • Side effects: none listed

Insane Labz Nightmare

This is another supplement type of product that is added to water before bedtime.

Not much information is available about the product, which is labeled as a blend of amino acids that promote healthy sleep.

Nightmare sleep aid is one product in the larger Insane Labz supplement program for athletes.

  • Dosage: 1 scoop added to water before bedtime
  • Warnings: none given
  • Side effects: none listed

Pros and Cons

Kirkland Sleep Aid Pros and Cons

Now I lay me down to sleep. For some of us, getting a full night’s sleep is as easy as sinking into a well-fluffed pillow. For others, sleep can be a bit more elusive.

The research is clear, sleep is not only rejuvenating but absolutely essential for maintaining good health and overall well being.

Most of us know the importance of getting a good night’s sleep, but few of us actually experience a full night’s rest.

When searching for sleep support, comparing over-the-counter sleep aids can be daunting. Here is a simple breakdown of the pros and cons of one such over the counter sleep support option, Kirkland Signature Sleep Aid.

The active ingredient in Kirkland Signature Sleep Aid is doxylamine succinate. According to a 2017 research study shared by the National Institutes of Health, Signature Sleep Aid produced numerous positive effects and was found to promote:

  • Decreased incidence of daytime sleepiness
  • Overall improved sleep quality

While the use of Kirkland Sleep Aid produced some desired effects, minimal negative effects have also been reported and may include:

  • Dizziness
  • Headache
  • Constipation
  • Upset stomach
  • Dry mouth


How Much Does it Cost?

Kirkland Sleep Aid costs $10.36 online. A money-back guarantee is vague, leaving suspicion about its validity.

“This is the best sleeping pills I’ve ever tried. Although I don’t take them often, sometimes if I have a long 8-10h flight or cant fall asleep for any reason. I’ve never took more than half of the pill ,and it put me asleep in 10-15min for about 8 hours.”

“I will never use this again it raised my blood pressure and made me dizzy with headach and belly pain.”

“Knocked me out but left me groggy and headachy for the day.”

Bottom Line

The Bottom Line on Kirkland Sleep Aid

Is Kirkland Sleep Aid the best in the business? Well, the short answer is…not really. We like that there’s only one ingredient in the mix and there’s no doubt it is associated with drowsiness, but we have some reservations. The price is a little high when you can find a generic for less and the reported side effects may be too much for some. Also, getting good rest is a critical part of weight-loss and if this product does cause lasting adverse reactions, dieters will have to weigh the pros versus the cons.

We honestly believe that weight loss is about more than just eating less and moving more. Sleep plays a huge role. We also support using an effective lifestyle program to keep you on track.

Among all the weight-loss programs we’ve reviewed, the one that always stands out is Noom. It’s with human coaching and one-on-one support that you find your way to the lifestyle changes needed to lose weight and keep it off.

Plus, the people behind Noom have confidence the program will work so they’re offering a 14-day trial.

Learn More About Noom “

Over-the-Counter (OTC) Medications as Short-Term Sleep Aids

Over-the-counter medications for the treatment of a sleep problem are those that can be purchased without a prescription. Examples of popular over-the-counter sleep aids include:

  • Sleep-Eze
  • Sominex
  • Nytol
  • Unisom and others

OTC sleep medications should only be used on a short term basis, since extended use of these medications can actually exacerbate insomnia. According to the American Academy of Sleep Medicine, antihistamine (usually diphenhydramine hydrochloride or doxylamine succinate) is the most common ingredient in OTC sleep aids.

See Using Medication to Manage Pain and Reduce Sleep Problems

The OTC sleep medications rely on the sedating effects of the antihistamine to facilitate sleep. If patients attempt to use an OTC sleep aid, they should immediately discontinue use if they experience any adverse side effects such as:

  • Dry mouth
  • Dry eyes
  • Urinary retention
  • Confusion (especially in the elderly)
  • Drowsiness the following day
  • Forgetfulness
  • Constipation
  • Blurred vision

Tolerance to the sedative effects of antihistamines can develop quickly—the longer they are taken the less likely they are to induce sleep. Many over-the-counter sleep aids can result in the person feeling groggy and unwell the next day. This is the so-called hangover effect. Also, these sleep medications may interact negatively with other medications, so a doctor should be consulted prior to using these for a sleeping problem.


It should also be noted that the sleep that is experienced when taking over-the-counter sleeping aids is not of the same quality as normal sleep. Research has demonstrated that some people who take OTC sleep aids spend as little as 5 percent of their total sleep time in deep sleep as compared to approximately 10 percent to 25 percent in healthy sleepers.

See Pain and Sleeping Problems Need to be Treated Together

In This Article:

  • Treating Insomnia with Non-Prescription Sleep Aids
  • Over-the-Counter (OTC) Medications as Short-Term Sleep Aids
  • Natural Remedies and Herbal Supplements as Sleep Aids
  • Using Supplements, Natural Remedies and OTC Sleep Aids Safely
  • Video: 11 Unconventional Sleep Tips: How to Get to Sleep and Stay Asleep

Diphenhydramine or Doxylamine?

Since almost all OTC sleep aides contain either diphenhydramine hydrochloride or doxylamine succinate, the choice is basically between these two active ingredients. The following information may help in making an informed decision between these two medications.

See Psychological Techniques, Sleep Environment, and Better Sleep


    Diphenhydramine is eliminated quickly from the body and most individuals don’t experience any lingering grogginess from the medicine the next day. Tolerance to this particular antihistamine builds up quickly and it loses its effectiveness as a sleep aid after just a few nights of repeated use. In general, diphenhydramine is less expensive than doxylamine. Since its use is associated with less of a hangover effect, and is milder than doxylamine, it is usually a good first choice in this category of and OTC sleep aid.

    • Diphenhydramine is the active ingredient in Sleep Eze, Sominex, Nytol, Tylenol PM, and Unisom SleepGels

    Doxylamine succinate
    Doxylamine succinate is one of the most sedating antihistamines available over-the-counter (stronger than diphenhydramine). A single dose causes rapid and marked drowsiness in the vast majority of individuals. Doxylamine succinate is eliminated somewhat more slowly from the body than diphenhydramine hydrochloride. As such, it will help the individual stay asleep longer but also may have a “hangover” effect the next day. Unlike diphenhydramine, most people don’t develop a tolerance to the sedating effects of doxylamine succinate.

    • Doxylamine is the active ingredient in Kirkland Sleep Aid (Costco) and Unisom SleepTabs

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