Benadryl Side Effects
Generic name: diphenhydramine
Medically reviewed by Drugs.com. Last updated on Oct 4, 2021.
Note: This document contains side effect information about diphenhydramine. Some of the dosage forms listed on this page may not apply to the brand name Benadryl.
For the Consumer
Applies to diphenhydramine: oral capsules and tablets, parenteral injection
Side effects include:
Sedation, sleepiness, dizziness, disturbed coordination, epigastric distress, thickening of bronchial secretions.
For Healthcare Professionals
Applies to diphenhydramine: compounding powder, injectable solution, oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating
The most commonly reported side effects included somnolence, dizziness, and incoordination.[Ref]
Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance
Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsions
Drowsiness usually diminishes after a few days.[Ref]
Common (1% to 10%): Dry mouth
Common (1% to 10%): Fatigue
Rare (0.01% to 0.1%): Confusion, depression, sleep disturbances
Rare (0.01% to 0.1%): Blood disorders
Rare (0.01% to 0.1%): Hypersensitivity reactions
Rare (0.01% to 0.1%): Liver dysfunction[Ref]
Frequency not reported: Blurred vision, dry eyes, diplopia[Ref]
Frequency not reported: Increased appetite, anorexia[Ref]
Frequency not reported: Muscle twitching/weakness[Ref]
Frequently asked questions
- What are the effects of taking expired benadryl?
- How much Benadryl can I take? What is too much?
- How much Benadryl can I give my dog?
- What is the max dose of diphenhydramine for adults?
- What is the dosage amount of children's Benadryl to give a 4 year old child who weighs 30 lbs?
- Does diphenhydramine raise blood pressure?
- Can diphenhydramine be used as a sleep aid?
- Diphenhydramine Hydrochloride vs Citrate: What's the difference?
More about Benadryl (diphenhydramine)
- Drug interactions
- Dosage information
- During pregnancy or Breastfeeding
- Reviews (63)
- Patient tips
- Drug images
- Compare alternatives
- Pricing & coupons
- En español
- Drug class: anticholinergic antiemetics
- Latest FDA Alerts (3)
Related treatment guides
1. "Product Information. Benadryl (diphenhydramine)." Parke-Davis (2002):
2. "Product Information. Benadryl Childrens Allergy Fastmelt (diphenhydrAMINE)." Pfizer U.S. Pharmaceuticals Group, New York, NY.
3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
4. Cerner Multum, Inc. "Australian Product Information." O 0
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.