Histamine is a chemical that is released in the body in response to inflammation or allergy, traveling throughout the body and searching for specific histamine receptors (targets on cells). Once attached to the receptors, histamine will cause swelling, itchiness and other symptoms associated with an allergic reaction. Diphenhydramine, the generic of Benadryl, is an antihistamine that inhibits the action of histamine, particularly its effect on H1 receptors. This drug is not approved for use in animals by the Food and Drug Administration but it is prescribed legally by veterinarians as an extra-label drug.
Who's Diphenhydramine For?
- Used primarily to treat allergic symptoms, itchy skin and allergic reactions, such as one caused by a drug or an insect bite
- Used to treat motion sickness and vomiting because of effects on the brain and nervous system
Side Effects and Warnings
- Diphenhydramine should not be used in animals with known hypersensitivity or allergy to the drug
- Animals with glaucoma, lung disease, heart disease, an overactive thyroid, high blood pressure or prostate enlargement should not use diphenhydramine
- Diphenhydramine may interact with other medications including epinephrine, tranquilizers, heparin and barbiturate
- Consult with your veterinarian to determine if other drugs your pet is receiving could interact with diphenhydramine
- Common side effects are sedation, lethargy, vomiting, diarrhea and lack of appetite.
- To cats, oral diphenhydramine is bitter and can cause profuse, yet temporary, drooling
- Consult your veterinarian regarding any allergies your pet may have, and any other side effects of this medication
Use as directed by your veterinarian