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Diphenhydramine HCl intramusc.

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.





This medication provides relief of symptoms of allergic reactions such as rash, hives, watery eyes, runny nose, itchy eyes and sneezing. Also used to treat motion sickness, anxiety, tension, sleeplessness or involuntary movements due to the side effects of certain psychiatric drugs.

How To Use

This medication is injected into a vein or into a muscle. Be sure you learn the proper technique of injecting this drug and of proper disposal procedures. Follow doctor's directions carefully. Do not use more often than prescribed.

Side Effects

May cause drowsiness, dizziness, headache, loss of appetite, stomach upset, vision changes, irritability and dry mouth and nose. These effects should subside as your body adjusts to the medication. If they persist or become bothersome, inform your doctor. Notify your doctor if you develop: breathing difficulties, heart pounding or irregular heartbeat, ringing in the ears, difficulty urinating. If you notice other effects not listed above, contact your doctor or pharmacist.


Tell your doctor if you have: heart problems, high blood pressure, overactive thyroid, lung disease, asthma, glaucoma, ulcers, enlarged prostate, drug allergies. May cause dizziness especially when rising quickly from a seated or lying position. Change positions slowly and be careful on stairs. May cause drowsiness. Use caution engaging in activities requiring alertness. Avoid the use of alcohol or other sedating type medications to avoid excessive drowsiness. Do not take for several days before allergy testing. Test results can be affected. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. This drug is excreted into breast milk and either the drug or breast-feeding must be discontinued. Consult your doctor.

Drug Interactions

Tell your doctor of any over-the-counter or prescription medication you may take, including: sedatives, tranquilizers, medications for depression, narcotic pain relievers (e.g., codeine). Check the labels on all your medicines because they may also contain diphenhydramine. This includes diphenhydramine either taken by mouth or applied to the skin (e.g., anti-itch cream, ointment, or spray). Ask your pharmacist about the safe use of those products. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include drowsiness, dizziness, dry mouth, flushing, fever, weakness, tremor, muscle twitching, loss of consciousness, and seizures. In children, excitement may occur first followed by loss of coordination, drowsiness, loss of consciousness, and seizures.


Do not share this medication with others.

Missed Dose

If you miss a dose, use it as soon as remembered; do not use if it is almost time for the next dose. Instead skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.


Store at room temperature between 59 and 86 degrees F (between 15 and 30 degrees C) away from moisture and sunlight. Do not store in the bathroom.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).