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Clemastine

First-Generation Antihistamine (H1 Blocker)
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
2 available
Formulations
1

Mechanism of action

Competitive H1-receptor antagonist that blocks histamine-mediated vasodilation, increased vascular permeability, and pruritus. Moderate anticholinergic and sedative properties.

At a glance

Class
First-Generation Antihistamine (H1 Blocker)
Schedule
OTC
Storage
Store at room temperature, protect from moisture

Dosing

🐕

Dog

Used for allergic dermatitis, urticaria, and pruritus
Dose
0.05–0.1 mg/kg
Route
PO
Frequency
q12h
🐈

Cat

Used for feline allergic skin disease
Dose
0.34–0.68 mg/cat
Route
PO
Frequency
q12h

Formulations

💊

Other — 1

Strength

Storage

Store at room temperature, protect from moisture

Safety

Monitoring parameters

Pruritus responseSedation level

Interactions

No documented interactions.

Brands

Other markets

Tavist
Dayhist

FAQs

Frequently asked questions

What is Clemastine?
Clemastine is a first-generation antihistamine (h1 blocker) used in pets. Competitive H1-receptor antagonist that blocks histamine-mediated vasodilation, increased vascular permeability, and pruritus. Moderate anticholinergic and sedative properties.
What is Clemastine used for in pets?
Clemastine is used in veterinary medicine for: Used for allergic dermatitis, urticaria, and pruritus; Used for feline allergic skin disease.
What is the Clemastine dose for dogs?
For dogs, Clemastine is typically dosed as follows — Used for allergic dermatitis, urticaria, and pruritus: 0.05–0.1 mg/kg PO q12h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Clemastine dose for cats?
For cats, Clemastine is typically dosed as follows — Used for feline allergic skin disease: 0.34–0.68 mg/cat PO q12h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Clemastine need a prescription?
Clemastine is available over the counter. Even so, you should consult your veterinarian before giving any medication to your pet.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Related medicines

Other medicines in the same class (First-Generation Antihistamine).

Chlorpheniramine
Competitively blocks histamine H1 receptors, reducing allergic symptoms including pruritus, urticaria, and oedema; crosses the blood-brain barrier causing sedation
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Diphenhydramine
Competitively blocks H1 histamine receptors on effector cells, preventing histamine-mediated vasodilation, increased vascular permeability, and pruritus; also has anticholinergic, antitussive, and mild sedative properties
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