Diphenhydramine Oral for Allergies

Medically reviewed by a licensed pharmacist · Last reviewed 6/11/2026

Dose

25mg by mouth every 4-6 hours, max 150mg/day. Ages 6-11: 12.5mg every 4-6 hours, max 75mg/day. May cause drowsiness; avoid alcohol and driving.

What to watch for

  • Sedative use
  • Narrow angle glaucoma
  • Bph urinary retention

Not for children under 6.

Sources

  • FDA OTC Monograph

Where to buy

This page is for general education and is not medical advice. It does not replace a consultation with a licensed pharmacist or your clinician. Always read and follow the product label. If symptoms are severe, worsening, or persistent, seek professional care.

Diphenhydramine Oral for Allergies: Uses, Dosing & What to Watch For | Pharmacy360 — Pharmacy360