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Doxylamine Succinate, Oral

What are other names for this medicine?

Type of medicine: antihistamine; sedative

Generic and brand names: doxylamine succinate, oral; Unisom SleepTabs; Unisom SleepGels

What is this medicine used for?

This medicine is taken by mouth to help you fall asleep. It contains an antihistamine that causes drowsiness.

What should my healthcare provider know before I take this medicine?

Do not take this medicine without your healthcare provider's approval if you have:

  • glaucoma
  • breathing problems such as asthma or emphysema
  • an enlarged prostate gland.

Females of childbearing age: Tell your healthcare provider if you are pregnant or plan to become pregnant. Do not breast-feed while taking this medicine without your healthcare provider's approval.

How do I take it?

Take this medicine exactly as your healthcare provider prescribes. If your healthcare provider has not given you specific instructions, follow the directions that come with the medicine package. Take the medicine 30 minutes before you go to bed. If you take the medicine during the night, you may be drowsy the next day. Do not take more or take it longer than prescribed. Ask your healthcare provider or pharmacist about anything you do not understand.

What should I watch out for?

Do not give this medicine to children under 12 years old unless your healthcare provider approves.

If you still have trouble sleeping after taking this medicine for more than 2 weeks, tell your healthcare provider. You may have a medical problem that is causing your sleeping problem.

This medicine causes drowsiness. Do not drive or operate machinery until you are fully alert.

You may feel dizzy or faint when you get up quickly after sitting or lying down. Getting up slowly may help.

This medicine increases the effects of alcohol and other drugs that slow down your nervous system. Do not drink alcohol or take other medicines unless your healthcare provider approves.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your healthcare provider if you have any side effects that continue or get worse.

Serious (report these to your healthcare provider right away): Trouble urinating, rapid heartbeat, seizures.

Other: Dry mouth, nausea, vomiting, blurred vision, dizziness, headache, loss of appetite.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your healthcare provider if you are taking:

  • herbs such as kava, St. John's wort, gotu kola, and valerian
  • muscle relaxants such as tizanidine (Zanaflex), cyclobenzaprine (Flexeril), carisoprodol (Soma), methocarbamol (Robaxin), and baclofen (Lioresal)
  • narcotic analgesics (painkillers) such as codeine, hydrocodone (Vicodin, Lortab), oxycodone (Percocet, Tylox, OxyContin), propoxyphene (Darvocet N-100), meperidine (Demerol), and fentanyl (Duragesic, Actiq)
  • other antihistamines such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), loratadine (Claritin), fexofenadine (Allegra), and cetirizine (Zyrtec)
  • sleeping pills such as phenobarbital, butabarbital (Butisol), flurazepam (Dalmane), pentobarbital (Nembutal), secobarbital (Seconal), zolpidem (Ambien), zaleplon (Sonata), and eszopiclone (Lunesta)
  • tranquilizers such as diazepam (Valium), chlordiazepoxide (Librium), lorazepam (Ativan), and alprazolam (Xanax).

Do not drink alcohol while you are taking this medicine without your healthcare provider's approval.

Keep a list of all your medicines (prescription, nonprescription, supplements, natural remedies, and vitamins) with you. Be sure that you tell all healthcare providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.


This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your healthcare provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.

Developed by McKesson Corporation
Published by McKesson Corporation.
Last modified: 2006-07-26
Last reviewed: 2006-05-04
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright © 2007 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.
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