Pet Medication 101: Benadryl It’s important to understand a medication’s uses and side effects before giving it to your pet. This medication info sheet is meant to give you a good understanding of what Benadryl (diphenhydramine) is used for, how it works, and potential side effects in cats and dogs. Always consult a veterinarian before giving your pet any medication. Are you concerned about your pet?Book a video consultation with an experienced veterinarian within minutes.Professional vet advice onlineLow-cost video vet consultationsOpen 24 hours a day, 365 days a year Book Video Consultation 1. Drug Name:diphenhydramine2. Common Name or Brand Name(s):Benadryl3. How Dispensed:Over-the-counter and prescription4. Forms:capsule, liquid, injectable, shampoo, topical spray. Multiple strengths are available so be sure to read the label carefully.5. Drug Type/Class:Antihistamine6. Uses for Cats and Dogs:Motion sickness, sedation, anaphylaxis and allergic reactions, atopy, mast cell tumors7. How it Works: Diphenhydramine is a first-generation antihistamine. It competitively inhibits H1 receptors, blocking the action of histamine, a substance in the body that is responsible for allergic symptoms.8. Side Effects and/or Signs of Overdose:Excessive sleepiness, dry mouth, urine retention. May causes excitement, especially in cats.9. Drug Interactions:Can cause excessive sleepiness when use with depressant drugs.10. Cautionary Statements:Diphenhydramine is generally safe to use under the direction of a veterinarian. Do not use in pets with glaucoma, hyperthyroidism, hypertension, seizure disorders, heart disease, or in neonates.Read more:How to Give Your Dog Oral MedicationHow to Give Your Cat Oral MedicationNeed to speak with a veterinarian regarding your pet's medication or another condition?Click here to schedule a video consult to speak to one of our vets. You can also download the FirstVet app from the Apple App Store and Google Play Stores.