Diphenhydramine is an antihistamine sometimes used as a sleep aid. Magnesium salicylate is a nonsteroidal anti-inflammatory drug (NSAID) in a group of drugs called salicylates (sa-LIS-il-ates).

Doans PM is a combination medicine that is used to treat back pain that keeps you awake during your normal sleeping hours.

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

Use this medicine exactly as directed. Taking too much diphenhydramine can lead to serious heart problems, seizures, coma, or death.

Magnesium salicylate may cause stomach or intestinal bleeding, which can be fatal. Call your doctor at once if you have symptoms of stomach bleeding such as dizziness, black or bloody stools, or coughing up blood.

Ask a doctor before giving the medicine to a child younger than 12 years old. Do not give this medicine to a child or teenager with a fever, flu symptoms, or chickenpox. Do not use this medicine to make a child sleepy.

Use exactly as directed on the label, or as prescribed by your doctor.

Taking too much diphenhydramine can lead to serious heart problems, seizures, coma, or death.

Take this medicine with a full glass of water before bedtime.

Take with food if this medicine upsets your stomach.

Do not use this medicine to make a child sleepy.

Stop taking this medicine and call your doctor if your pain does not improve, or if it gets worse after 10 days of using this medicine. Tell your doctor if you have a fever that lasts longer than 3 days, or if you have any redness or swelling.

If you need surgery or dental work, tell the surgeon or dentist ahead of time that you are using Doans PM. You may need to stop using the medicine for a short time.

This medicine can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using Doans PM.

Store at room temperature away from moisture and heat.

You should not use Doans PM if you are allergic to aspirin or other salicylates.

Do not give this medicine to a child or teenager with a fever, flu symptoms, or chickenpox. Salicylates can cause Reye's syndrome, a serious and sometimes fatal condition in children. Ask a doctor before giving the medicine to a child younger than 12 years old.

Magnesium salicylate may cause stomach or intestinal bleeding, which can be fatal. These conditions can occur without warning while you are using magnesium salicylate, especially in older adults.

Ask a doctor or pharmacist if this medicine is safe to use if you have ever had:

• bleeding problems;

• heartburn, stomach ulcer, or stomach bleeding;

• an enlarged prostate or urination problems;

• asthma or COPD, cough with mucus, or cough caused by smoking, emphysema, or chronic bronchitis;

• heart disease, high blood pressure;

• liver disease, cirrhosis, or if you drink more than 3 alcoholic beverages per day;

• kidney disease;

• arthritis, gout;

• diabetes;

• glaucoma; or

• a thyroid disorder.

Ask a doctor before using this medicine if you are pregnant or breastfeeding.

Taking this medicine during the last 20 weeks of pregnancy may cause serious kidney problems in the unborn baby, or bleeding in the mother or the baby during delivery.

Since Doans PM is used when needed, you may not be on a dosing schedule. Skip any missed dose if it's almost time for your next dose. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of diphenhydramine can be fatal.

Overdose symptoms may include vomiting, confusion, severe drowsiness, ringing in your ears, no urination, very dry eyes and mouth, dilated pupils, fast heartbeats, tremor, agitation, hallucinations, or seizure.

Avoid driving or hazardous activity until you know how Doans PM will affect you. Your reactions could be impaired.

Also ask a doctor or pharmacist before using any other medicine that may contain diphenhydramine or ingredients similar to magnesium salicylate (such as aspirin or other salicylates). This includes medicines for pain, fever, swelling, sleep, cold/allergy symptoms, or anti-itch medicine used on the skin. Using too much diphenhydramine may lead to a fatal overdose.

Avoid alcohol. Heavy drinking can increase your risk of stomach bleeding.

Get emergency medical help if you have signs of an allergic reaction: hives; wheezing, difficult breathing; feeling light-headed; swelling of your face, lips, tongue, or throat.

Doans PM may cause serious side effects. Stop using Doans PM and call your doctor at once if you have:

• severe drowsiness;

• painful or difficult urination;

• ringing in your ears, hearing loss;

• confusion; or

• signs of stomach bleeding--feeling light-headed, ongoing stomach pain, bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds.

Common side effects of Doans PM may include:

• drowsiness;

• dry eyes, blurred vision;

• dry mouth, nose, or throat;

• decreased urination;

• heartburn, nausea, vomiting, gas;

• constipation;

• feeling restless or excited (especially in children); or

• day-time drowsiness or "hangover" feeling after night-time use.

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.

Ask a doctor or pharmacist before using this medicine with any other drugs that can cause drowsiness (such as opioid medication, sleep medicine, a muscle relaxer, or medicine for anxiety or seizures).

Ask a doctor or pharmacist if it is safe for you to use Doans PM if you are also using:

• a blood thinner--warfarin, Coumadin, Jantoven;

• other NSAIDs (nonsteroidal anti-inflammatory drugs)--aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others;

This list is not complete. Other drugs may affect Doans PM, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.