ExoticRx · exoticrx.com/drugs/diphenhydramine
US brand names:Benadryl
Diphenhydramine is dosed at 2–4 mg/kg PO q8-12h in dogs, per Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.437 (2026-08-01).. Verify against current literature before clinical use.
Competitive antagonist at histamine H1 receptors. Also has anticholinergic, anti-motion sickness, and mild sedative properties.
Sedation common (first-generation). Anticholinergic effects (dry mouth, urinary retention). Ensure product does not contain xylitol or pseudoephedrine. Dogs and cats. Less effective than second-gen antihistamines for pruritus.
Species references:All Cat (Domestic) drugsAll Dog (Domestic) drugs
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A dog/cat sample is shown here. Cited dosing for all 2 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.
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