Table 3: Oral Antihistamine Doses for Dogs
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| Drug Name | Dose |
|---|---|
| Hydroxyzine | 2 mg/kg q 12 hr1 |
| Cetirizine | 1–2 mg/kg q 24 hr1 |
| Chlorpheniramine | 0.4 mg/kg q 12 hr2 |
| Cyproheptadine | 0.3–2 mg/kg q 12 hr2 |
| Clemastine | 0.05–1 mg/kg q 12 hr2 |
| Loratadine | 1 mg/kg q 12 hr2 |
| Fexofenadine | 5–15 mg/kg q 24 hr3 |
| Amitriptyline | 1–2 mg/kg q 12 hr2 |
| Diphenhydramine | 2–3 mg/kg q 12 hr2
Questionable efficacy if given orally4 |
- Bizikova P, Papich MG, Olivry T. Hydroxyzine and cetirizine pharmacokinetics and pharmacodynamics after oral and intravenous administration of hydroxyzine to healthy dogs. Vet Dermatol. 2008;19:348–57.
- Miller WH, Griffin GE, Campbell KL. Muller & Kirk’s Small Animal Dermatology. 7th ed. St. Louis:Elsevier;2013.
- Plevnik A, Kobal S, Domanjko-Petric A, et al. The efficacy of antihistamine fexofenadine versus methylprednisolone in the treatment of atopic dermatitis in dogs. Slov Vet Res. 2009;46:5–12.
- Banovic F, Denley T, Blubaugh A, et al. Effect of diphenhydramine and cetirizine on immediate and late-phase cutaneous allergic reactions in healthy dogs: a randomized, double-blinded crossover study. Vet Dermatol. 2020;31:256–e58.
The 2023 AAHA Management of Allergic Skin Diseases in Dogs and Cats Guidelines are generously supported by Hill’s Pet Nutrition, Merck Animal Health, and Zoetis.
