Transparency Disclosure — We may receive a referral fee for products purchased through the links on our site…Read More.

What Are Doxylamine Succinate Tablets?

Recent data shows that one in five U.S. adults struggle to sleep every night1, with half of adults experiencing insomnia once a month or more. If you fall into these categories, you may have come across doxylamine succinate, which is the active ingredient in drugstore sleep aids like Unisom. It’s also sold as a generic tablet. 

Since 1978, doxylamine succinate has been approved by the U.S. Food and Drug Administration as an over-the-counter sleep aid2. If you’re struggling to sleep and thinking of purchasing some, read on to find out how it works, if it’s safe, and what the potential side effects are. Plus, if you’re not sure if taking a sleeping aid is the right avenue for you, we’ve got some great advice on small changes you can make that could help you sleep more easily. 

Doxylamine Succinate Tablets

Doxylamine succinate is an antihistamine that has anticholinergic and sedative effects..2 Anticholinergics suppress the parasympathetic nervous system3, which is the body’s “rest and digest” state; this can be useful for treating a wide range of ailments, such as respiratory disorders, psychiatric disorders, depression, cardiovascular disease, and allergies. Additionally, anticholinergic medications can have a sedating effect4.

When combined with pyridoxine (vitamin B6), doxylamine succinate is approved by the FDA5 for the treatment of pregnancy nausea and vomiting. Doxylamine succinate is available over the counter as delayed-release or extended-release tablets, which are taken orally6. You can purchase branded or generic versions.

Do Doxylamine Succinate Tablets Help You Sleep?

Doxylamine succinate tablets can help you sleep as they’re part of a group of medicines called antihistamines. These medicines inhibit the action of histamines7, which are chemicals in the body that cause allergy symptoms. Histamines also play a part in helping you feel awake8, and antihistamines can disrupt this, making you feel drowsy.

The advised dosage for short-term insomnia is a 25-milligram tablet taken 30 minutes before going to bed.5 However, the body can quickly become tolerant to this medicine, so it will eventually stop working9 and should not be used as a long-term sleep solution.

Are Doxylamine Succinate Tablets Safe?

When used as intended, doxylamine succinate tablets are considered safe4, and while safety and efficacy are yet to be fully understood, the FDA has approved this medicine as a sleep aid.5, 6

However, doxylamine succinate is not intended to be used for longer than two weeks as a sleep aid as efficacy will decrease after time, and there’s not enough evidence on its safety for long-term use.6, 8 Speak to your doctor if you’re having persistent trouble sleeping as there may be an underlying cause. 

This medicine should not be used as a sleeping tablet for children under the age of 12.6 

Doxylamine succinate may interact with other medication10, including MAOIs (an early type of antidepressant), sedatives, and allergy medications. If you take other medication or supplements, talk with your doctor before self-medicating with doxylamine succinate. Alcohol can also increase the sedative effects of the drug11, so this should be limited or avoided altogether. 

As this medicine can make you drowsy, it’s advised to avoid driving or operating machinery until you’ve established how your body reacts to it.10

Potential Doxylamine Succinate Tablets Side Effects

As with all medicine, you may experience some unwanted side effects when taking doxylamine succinate.10 These include:

  • Dry mouth
  • Constipation
  • Dizziness
  • Drowsiness
  • Confusion. 

Side effects that should be reported to your healthcare provider include allergic reactions, trouble passing urine, and eye pain or blurred vision.10 The elderly may also experience more severe side effects, such as confusion or falls.9 

Who Should Use Doxylamine Succinate Tablets?

Doxylamine succinate can be used as a short-term sleep aid for adults and children over the age of 12, for no more than two weeks.

It also works in the treatment of allergic rhinitis (hay fever) and can be taken by both adults and children for this use. People experiencing pregnancy nausea or vomiting can purchase doxylamine succinate and pyridoxine hydrochloride delayed-release tablets, which should be taken regularly to reduce symptoms.6

Who Should Avoid Taking Doxylamine Succinate Tablets

If you have any of the following conditions, you should speak to your healthcare provider before taking medication containing doxylamine succinate.10

  • Heart disease
  • Liver disease
  • Glaucoma
  • Respiratory disease
  • Trouble passing urine
  • Stomach problems
  • Prostate issues

If you’re breastfeeding, pregnant, or trying to get pregnant, you should also check with your doctor.10

People who have an alcohol or illegal drug addiction should avoid taking doxylamine succinate as this can interact negatively with these substances.11 

Those taking other prescribed or over-the-counter medicine should confirm with their doctor that it’s safe to mix these with doxylamine succinate. Lastly, older patients may experience more severe side effects from this medicine, so it’s best to speak with your healthcare provider or pharmacist before self-medicating.9

Tips for Better Sleep Without Medication

If you’re struggling to fall asleep at bedtime or regularly waking in the night, there are multiple practices you can do to help boost your chances of getting a good night’s rest.

  • Have a relaxing nightly routine – Establish a bedtime routine for yourself that will help you relax, such as reading a book or taking a warm bath. 
  • Cut off screen devices before bed – While it can feel relaxing to lie in bed and scroll social media, the blue light emitted from your phone screen can wreak havoc with your sleep cycle. Research shows that blue light suppresses melatonin productionn12, an important hormone for promoting sleep at night. Therefore, avoid using screen devices in the lead-up to bedtime, ideally for at least an hour if possible.
  • Avoid smoking, caffeine, and alcohol – You should also avoid nicotine and caffeine too close to bedtime as these are stimulants that can prevent you from falling asleep13. Additionally, refrain from drinking too much alcohol; while it can have an initial sedative effect, you’ll likely experience poor quality or disrupted sleep.13 
  • Make your bedroom conducive to sleep – Your bedroom should be kept like a cave for optimum sleep – dark, quiet, and cool. The optimum sleep temperature for most adults is 60 to 67 degrees Fahrenheit14.  Although this is a recommended range, your priority should be a temperature comfortable for you and your sleeping partner. Sleeping at a temperature that is too hot or cold for you could make it harder to sleep well.
  • Consider melatonin supplements – You can also try taking a supplement that contains a synthetic version of melatonin. These are not sedatives, but they could increase the amount of melatonin in your system, which may help you feel more sleepy at bedtime. However, consult your healthcare provider before incorporating supplements into your routine.

If you’re experiencing long-term sleep issues that affect your day-to-day life, you should speak with your doctor, as there may be an underlying medical issue. 

Frequently Asked Questions 

Is doxylamine succinate a sleeping pill?

Doxylamine succinate is a drugstore medicine that’s used to treat short-term insomnia, as it’s an antihistamine that causes drowsiness. However, it should not be relied upon for chronic sleep problems, as it’s not intended to be used for longer than two weeks.6

Is doxylamine succinate the same as Benadryl?

Doxylamine succinate works in a similar way to Benadryl, which is a branded medicine that contains another antihistamine called diphenhydramine15. Like doxylamine succinate, diphenhydramine can be used to treat allergic reactions and act as a short-term sleep aid. 

However, diphenhydramine is also used to treat motion sickness, while doxylamine succinate can be used to treat pregnancy sickness.6, 15 

Doxylamine succinate is available as an oral tablet, while diphenhydramine can be taken as a capsule, liquid, or tablet16.

What are the disadvantages of doxylamine succinate?

Some people may experience side effects while taking doxylamine succinate, such as constipation, dry mouth, confusion, dizziness, and drowsiness.10 Take precautions when using this medication if you need to drive or operate machinery the next day. 

Serious but less common side effects include blurred vision, eye pain, problems passing urine, and allergic reactions. If any of these happen to you, contact a doctor immediately.10 

Older adults are also at risk of experiencing more severe reactions, including confusion or falls.9

Lisa Bowman

Lisa Bowman


About Author

Lisa is a content writer for Sleep Advisor, which combines two of her greatest passions – writing and sleeping. She can also be found writing about fitness, sustainability and vegan food.

Combination Sleeper


  1.  “Global Insomnia Statistics in 2022 & 2023”. Helsestart. Webpage accessed January 15, 2024. 
  2. Allison, Mark., Hale, Cecilia. “A Phase I Study of the Pharmacokinetics and Pharmacodynamics of Intranasal Doxylamine in Subjects with Chronic Intermittent Sleep Impairment”. StatPearls. 2018.
  3. Ghossein, Noah., Kang, Michael., Lakhkar, Anand D. “Anticholinergic Medications”. StatPearls. Last modified May 8, 2023. 
  4. Kumar, Suresh., et al. “Anticholinergic Burden, Sleep Quality and Health Outcomes in Malaysian Aged Care Home Residents.” National Library of Medicine. 2019
  5. Brott, Nathan R., Kumar, Anil., Reddivari, Reddy. “Doxylamine”. StatPearls. Last modified June 5, 2023. 
  6. “Doxylamine (Monograph)”. Last modified September 14, 2023. 
  7. “Histamine” Cleveland Clinic. Last modified March 28, 2023. 
  8. Parikh MD, Purvi. “When Allergy or Cold Medication Makes You Drowsy”. Allergy & Asthma Network. Webpage accessed January 23, 2024.
  9. “Are drugstore sleep aids safe?”. Harvard Health Publishing. 2021.
  10.  “Doxylamine Tablets”. Cleveland Clinic. Webpage accessed January 15, 2024. 
  11. “Doxylamine and Alcohol/Food Interactions”. Webpage accessed January 15, 2024. 
  12. Silvani, Marcia Ines., Werder, Robert.,  Perret, Claudio. “The influence of blue light on sleep, performance and wellbeing in young adults: A systematic review”. Frontiers in Physiology.  2022.
  13. “Sleep tips: 6 steps to better sleep”. Mayo Clinic. Last modified May 7, 2022.
  14.  “What’s the Best Temperature for Sleep?”. Cleveland Clinic. 2021.
  15. “Benadryl”. Last modified August 7, 2023. 
  16. “Comparing Diphenhydramine vs Doxylamine”. Webpage accessed January 15, 2024.