Diphenmax Side Effects
Generic Name: diphenhydramine
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 Diphenmax.
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
Frequency not reported: Paresthesia, dyskinesia/muscle dyskinesia, vertigo, neuritis, incoordination, psychomotor impairment, activation of epileptogenic foci[Ref]
Drowsiness usually diminishes after a few days.[Ref]
Common (1% to 10%): Fatigue
Frequency not reported: Lassitude, tinnitus, acute labyrinthitis, asthenia, chills, impaired performance (including impaired driving, work, and/or information processing)[Ref]
Rare (0.01% to 0.1%): Confusion, depression, sleep disturbances
Frequency not reported: Paradoxical excitation/excitation, agitation, increased energy, restlessness, nervousness, euphoria, anxiety, hallucinations, insomnia, irritability[Ref]
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]
1. Cerner Multum, Inc. "Australian Product Information." O 0
2. "Product Information. Benadryl (diphenhydramine)." Parke-Davis, Morris Plains, NJ.
3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
4. "Product Information. Benadryl Childrens Allergy Fastmelt (diphenhydrAMINE)." Pfizer U.S. Pharmaceuticals Group, New York, NY.
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.
More about Diphenmax (diphenhydramine)
- Diphenmax Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Interactions
- Support Group
- 0 Reviews – Add your own review/rating
- Drug class: anticholinergic antiemetics