Allegra Dog Dosage Calculator
Calculate fexofenadine (Allegra) doses for dogs with allergic skin disease — a non-sedating second-generation antihistamine with critical Allegra-D pseudoephedrine warning.
ALLEGRA-D IS TOXIC TO DOGS. Allegra-D and Allegra-D 24-Hour contain pseudoephedrine, which can cause life-threatening stimulant toxicity in dogs (hypertension, tachycardia, seizures). ONLY use plain Allegra (fexofenadine only). Check every label — never assume.
What Is Fexofenadine (Allegra) for Dogs?
Fexofenadine is a non-sedating, second-generation H1 antihistamine that selectively and peripherally blocks histamine H1 receptors. Unlike first-generation antihistamines (diphenhydramine, chlorphenamine), fexofenadine has minimal CNS penetration due to efflux by P-glycoprotein, making it non-sedating in most dogs. It is used as adjunct therapy for canine atopic dermatitis, allergic rhinitis, urticaria, and food allergies.
Antihistamines generally have limited efficacy as monotherapy for canine atopy, but provide benefit when combined with omega-3 fatty acids, topical therapy, or allergen-specific immunotherapy. Second-generation agents like fexofenadine are preferred over first-generation due to lower sedation risk and once-daily dosing convenience.
Available Forms
- 30 mg, 60 mg, 120 mg, 180 mg tablets
- 6 mg/mL oral suspension (for small dogs)
- ONLY plain Allegra — never Allegra-D (contains pseudoephedrine)
How to Use This Calculator
- Verify your product is plain fexofenadine — read all active ingredients
- Enter your dog’s weight
- Choose the tablet strength you have
- Click Calculate to see daily dose and tablet count
🧮 Fexofenadine Dose Calculator
Fexofenadine Dosing Result
References
- Plumb DC. Plumb’s Veterinary Drug Handbook, 9th ed. Wiley-Blackwell; 2018.
- Olivry T, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines. BMC Vet Res. 2015;11:210.
- ASPCA Animal Poison Control Center. Pseudoephedrine toxicity in dogs. 2023.