Benadryl Side Effects Center

What Is Benadryl?

Benadryl (diphenhydramine) is an antihistamine used to treat allergies, hives, insomnia, motion sickness, and mild cases of Parkinsonism. Benadryl is available in generic form and over-the-counter (OTC).

What Are Side Effects of Benadryl?

Common side effects of Benadryl include:

• drowsiness,
• fatigue,
• tiredness,
• sleepiness,
• dizziness,
• disturbed coordination,
• constipation,
• dry mouth/nose/throat,
• difficulty urinating or an enlarged prostate,
• upset stomach,
• blurred vision,
• double vision,
• tremor,
• loss of appetite,
• headache, or
• nausea.

Dosage for Benadryl

A typical dose of Benadryl is 25-50 mg every 4-6 hours.

What Drugs, Substances, or Supplements Interact with Benadryl?

Benadryl may interact with monoamine oxidase inhibitors (MAOIs), other over-the-counter cough, cold, allergy, or insomnia medications, anxiety or sleep medicines, antidepressants, or any other medications that make you feel drowsy, sleepy, or relaxed. Tell your doctor all medications and supplements you use.

Benadryl During Pregnancy and Breastfeeding

Benadryl has not been adequately evaluated in pregnant women. Benadryl is secreted in breast milk. Because of the risk of stimulation and seizures in infants, especially newborns and premature infants, antihistamines should not be used by nursing mothers.

Additional Information

Our Benadryl Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

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.

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

Stop using diphenhydramine and call your doctor at once if you have:

• severe drowsiness; or
• painful or difficult urination.

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

Common side effects may include:

• drowsiness;
• dry eyes, blurred vision;
• dry mouth, nose, or throat;
• decreased urination;
• 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.