Is doxylamine succinate addictive?

Doxylamine succinate is the active ingredient in Unisom sleep tablets (an over-the-counter sleep aid). It is an antihistamine with properties to make users drowsy. It can also be used to relieve hay fever symptoms and various additional allergies.

As with any sleep aid, instructions should be followed, as it could be addictive when used improperly.

The Facts

Before taking doxylamine (Unisom), be sure to talk to your doctor if you have COPD (chronic obstructive lung disease), asthma, high blood pressure, heart disease, glaucoma, chronic illness, liver disease, prostate difficulties, pain or difficulty urinating, ulcers or if you are pregnant, trying to get pregnant or are breastfeeding. Doxylamine tablets are administered orally with the common dosage being one 25 mg tablet taken 30 minutes before going to bed. Do not take this medication more often than once per day or in higher doses without consulting your doctor. After 2 weeks of taking the medication, if you are still having difficulty sleeping, contact your doctor.

Drug Interactions

Like any other medication, doxylamine succinate can interact with other drugs like alcohol, barbiturates, anxiety medications (like temazepam or diazepam), allergy medications, muscle relaxers, anti-depressants, anti-psychotics and prescription pain killers. Be sure to talk to your doctor or pharmacist about all of the medications that you are taking (including supplements, OTC medication and herbal treatments) to avoid any adverse reactions. If you drink caffeine or alcohol, smoke or use illegal drugs, these substances can affect the way that doxylamine succinate works.


If you are taking doxylamine for allergy relief and do not see any improvement within 1 to 2 days, contact your doctor for further advice. If you are taking it as a sleep-aid, do not take doxylamine for more than 2 weeks without contacting your health care professional. Watch out for fever, difficulty breathing or worsening of any allergy symptoms. This medication may make you dizzy or drowsy. As with any other sleep-aids, you should not drive or operate machinery until you know how the medication will affect you. This is imperative for older patients who may be prone to dizzy or fainting spells. Avoid alcohol when taking this medication.

Side Effects

Common side effects include nervousness, agitation, dry eyes, dry mouth, headache, loss of appetite, nausea, vomiting, diarrhoea, or constipation, dizziness, fainting, irregular heart beat or chest pain, muscle twitches, difficult urination and seizures. Additional side effects include allergic reactions (rash, swelling, hives and itching), confusion, vision changes and unusual bruising/bleeding. If you experience any of these symptoms, contact your doctor or pharmacist for guidance.

Avoiding Dependency

To avoid developing an addiction or dependence on this product, be sure to follow instructions on the package or prescription. Do not take larger doses or more frequent doses without medical advice. If you think that you've taken too much or overdosed, contain your doctor, poison control centre or emergency room immediately.