Unisom

Generic name: doxylamine [ dox-IL-a-meen ]
Drug class: Miscellaneous anxiolytics, sedatives and hypnotics

Medically reviewed by Drugs.com on Jan 1, 2025. Written by Cerner Multum.

What is Unisom?

Unisom is an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose. Antihistamines can cause drowsiness and are sometimes used a sleep aids.

Unisom is used to treat sneezing, runny nose, watery eyes, hives, skin rash, itching, and other cold or allergy symptoms.

Unisom is also used as a short-term treatment for sleep problems (insomnia).

Unisom may also be used for purposes not listed in this medication guide.

Unisom side effects

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

Unisom may cause serious side effects. Call your doctor at once if you have:

• confusion, hallucinations;

• severe dizziness or drowsiness; or

• little or no urinating.

Common side effects of Unisom may include:

• blurred vision;

• dry mouth, nose, or throat;

• constipation; or

• mild dizziness or drowsiness.

Side effects such as dry mouth, constipation, and confusion may be more likely in older adults.

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.

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Warnings

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.

Before taking this medicine

You should not use Unisom if you are allergic to it.

Ask a doctor or pharmacist if it is safe for you to take Unisom if you have other medical conditions, especially:

• glaucoma;

• an enlarged prostate;

• problems with urination; or

• asthma, bronchitis, emphysema, or other chronic lung disease.

Older adults may be more sensitive to the effects of this medicine.

Unisom is not expected to be harmful to an unborn baby. Do not use this medicine without a doctor's advice if you are pregnant.

Doxylamine may pass into breast milk and may harm a nursing baby. Antihistamines may also slow breast milk production. Do not use this medicine without a doctor's advice if you are breast-feeding a baby.

How should I take Unisom?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. This medicine is usually taken only for a short time until your symptoms clear up.

Do not use Unisom to treat insomnia in a child younger than 12 years old. Ask a doctor before using this medicine to treat cold or allergy symptoms in a child younger than 6 years old. Always ask a doctor before giving a cold or allergy medicine to a child. Death can occur from the misuse of these medicines in very young children.

Take this medicine with food or milk if it upsets your stomach.

To treat insomnia, it is best to take Unisom only when you can devote several hours to sleep. Follow your doctor's instructions.

Call your doctor if your cold or allergy symptoms do not improve after 7 days of treatment, or if your sleep problems do not improve after 2 weeks of treatment.

This medication can cause you to have unusual results with allergy skin tests. Tell any doctor who treats you that you are taking an antihistamine.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

When treating insomnia, if it is almost your normal waking hour, skip the missed dose and wait until you are ready for bed again.

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 forms of some of the side effects listed in this medication guide.

What should I avoid while taking Unisom?

Unisom may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Ask a doctor or pharmacist before using any other cold, cough, allergy, or sleep medicine. Many combination medicines contain antihistamines. Taking certain products together can cause you to get too much of this medicine.

Ask a doctor or pharmacist before using any other cold, cough, allergy, or sleep medicine. Antihistamines are contained in many combination medicines. Taking certain products together can cause you to get too much of a certain drug. Check the label to see if a medicine contains an antihistamine.

Drinking alcohol can increase certain side effects of doxylamine.

Avoid becoming overheated or dehydrated during exercise and in hot weather. Unisom can decrease sweating and you may be more prone to heat stroke.

What other drugs will affect Unisom?

Ask a doctor or pharmacist before using this medicine if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking Unisom with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

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Further information

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

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

Medical Disclaimer

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