Benadryl

Medical Editor: John P. Cunha, DO, FACOEP Last updated on RxList: 6/6/2023

Drug Summary

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?

Benadryl may cause serious side effects including:

  • pounding heartbeats or fluttering in your chest,
  • painful or difficult urination,
  • little or no urination,
  • confusion,
  • lightheadedness,
  • tightness in your neck or jaw, and
  • uncontrollable movements of your tongue

Get medical help right away, if you have any of the symptoms listed above.

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.

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheadedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

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.

Description for Benadryl

Benadryl® Allergy contains the histamine-blocker diphenhydramine. This product relieves: runny nose; sneezing; itchy, watery eyes; itchy throat.

Ingredient

Active ingredient
(in each capsule)		 Purpose
Diphenhydramine HCl 25 mg Antihistamine

Inactive ingredients

candelilla wax, colloidal silicone dioxide, crospovidone, hypromellose, microcrystalline cellulose, polyethylene glycol, providone, pregelatinized starch, starch, stearic acid, titanium dioxide, and talc

* Effects seen on total nasal symptoms with Benadryl® Allergy (diphenhydramine) 50 mg 3 times daily. Use as directed.

Uses for Benadryl

Benadryl® Allergy (diphenhydramine) Uses

  • temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:
    • runny nose
    • sneezing
    • itchy, watery eyes
    • itching of the nose or throat
  • temporarily relieves these symptoms due to the common cold:
    • runny nose
    • sneezing

Dosage for Benadryl

Directions

  • do not use more than directed (see OVERDOSE warning)

adults and children 12 years of age and over 25 mg to 50 mg (1 to 2 capsules).
children 6 to under 12 years of age 12.5 mg ** to 25 mg (1 capsule).
children under 6 years of age consult a doctor

**12.5 mg dosage strength is not available in Benadryl (diphenhydramine) ® Allergy Kapseals® Capsules.

Other information

  • store at 59° to 77°F in a dry place
  • protect from light

HOW SUPPLIED

Available in:
Ultratabs® tablets: Box of 24's, 48's, & 100's
Kapseals® capsules: Box of 24's & 48's

FDA rev date: 7/1/1997

Side Effects for Benadryl

When using this product:

  • marked drowsiness may occur
  • avoid alcoholic drinks
  • alcohol, sedatives, and tranquilizers may increase drowsiness
  • excitability may occur, especially in children
  • be careful when driving a motor vehicle or operating machinery

Drug Interactions for Benadryl

Ask a doctor or pharmacist before use if you are taking sedatives or tranquilizers.

Warnings for Benadryl

Alcohol warning: If you consume 3 or more alcoholic drinks every day, ask your doctor whether you should take acetaminophen or other pain relievers/fever reducers. Acetaminophen may cause liver damage.

Precautions for Benadryl

No information provided.

Overdose Information for Benadryl

Overdose warning: Taking more than the recommended dose may cause liver damage. In case of overdose, get medical help or contact a Poison Control Center right away. Quick medical attention is critical for adults as well as for children even if you do not notice any signs or symptoms

Contraindications for Benadryl

No information provided.

Clinical Pharmacology for Benadryl

No information provided.

Patient Information for Benadryl

Do not use

  • with another product containing any of these active ingredients
  • if you are now taking a prescription monoamine oxidase inhibitor (MAOI) (certain drugs for depression, psychiatric, or emotional conditions, or Parkinson's disease), or for 2 weeks after stopping the MAOI drug. If you do not know if your prescription drug contains an MAOI, ask a doctor or pharmacist before taking this product.
  • with any other product containing diphenhydramine, even one used on skin.

Ask a doctor before use if you have

Ask a doctor or pharmacist before use if you are taking sedatives or tranquilizers

When using this product

do not use more than directed

  • marked drowsiness may occur
  • avoid alcoholic drinks
  • alcohol, sedatives, and tranquilizers may increase drowsiness
  • be careful when driving a motor vehicle or operating machinery
  • excitability may occur, especially in children

Stop use and ask a doctor if

  • redness or swelling is present
  • sore throat is severe
  • you get nervous, dizzy, or sleepless
  • new symptoms occur
  • fever gets worse or lasts more than 3 days
  • pain, cough or nasal congestion gets worse or lasts more than 5 days (children) or 7 days (adults)
  • sore throat lasts for more than 2 days, is accompanied or followed by fever, headache, rash, swelling, nausea, or vomiting
  • cough comes back or occurs with rash or headache that lasts. These could be signs of a serious condition.

If pregnant or breast-feeding, ask a health professional before use.
Keep out of reach of children.

Questions?

call 1-800-524-2624 (English/Spanish), weekdays, 9 AM - 5 PM EST.

From WebMD Logo

Allergies Resources
Featured Centers
FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.