Diphenhydramine

This form:

Pronounced

"dye-fen-HI-druh-meen"

Common brand names:

Benadryl, Calmex, Nytol, Unisom

Uses

Diphenhydramine is an antihistamine used to relieve symptoms of allergy, hay fever, and the common cold. These symptoms include rash, itching, watery eyes, itchy eyes/nose/throat, cough, runny nose, and sneezing. It is also used to prevent and treat nausea, vomiting and dizziness caused by motion sickness. Diphenhydramine can also be used to help you relax and fall asleep.

This medication works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Its drying effects on such symptoms as watery eyes and runny nose are caused by blocking another natural substance made by your body (acetylcholine).

Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Therefore, do not use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products (such as long-acting tablets/capsules) are not recommended for use in children younger than 12 years. Ask your doctor or pharmacist for more details about using your product safely.

These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions. Do not use this product to make a child sleepy. Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).

Other Uses

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

Diphenhydramine is also used alone or with other medications to treat shaking (tremor) and muscle stiffness caused by Parkinson's disease. It may also be used to treat side effects of certain psychiatric drugs such as involuntary movements and muscle stiffness (such as EPS). It works by blocking acetylcholine (See also Uses section).

How to Use This Medication

Follow all directions on the product package. If your doctor has prescribed this medication, take it as directed. If you are uncertain about any of the information, consult your doctor or pharmacist.

Take the tablet, capsule, or liquid form by mouth with or without food. Measure liquid forms of this medication using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. If you have a single-dose form of this medication (such as a single-use whistle), you do not need to measure the dose.

The rapidly-dissolving tablet or strip should be allowed to dissolve on the tongue and then swallowed, with or without water. The chewable tablets should be chewed thoroughly before being swallowed.

The dosage is based on your age, medical condition, and response to treatment. There are many brands and forms of diphenhydramine available. Read the dosing instructions carefully for each product because the amount of diphenhydramine may be different between products. Do not increase your dose or take this medication more often than directed.

To prevent motion sickness, take your dose 30 minutes before starting activity such as travel. To help you sleep, take your dose about 30 minutes before bedtime. If you continue to have difficulty sleeping for longer than 2 weeks, contact your doctor.

Tell your doctor if your condition does not improve or if it worsens.

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Information expires December 2017.