Speak to a vet within minutes

4.9 On the App Store 3600+ reviews

Pet Medication 101: Benadryl

benadryl for pets

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.

1. Drug Name:


2. Common Name or Brand Name(s):


3. How Dispensed:

Over-the-counter and prescription

4. Forms:

capsule, liquid, injectable, shampoo, topical spray. Multiple strengths are available so be sure to read the label carefully.

5. Drug Type/Class:


6. Uses for Cats and Dogs:

Motion sickness, sedation, anaphylaxis and allergic reactions, atopy, mast cell tumors

7. 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 Medication

How to Give Your Cat Oral Medication

Need 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.

More articles about dog

Are you concerned about your pet?

Book a video consultation with an experienced veterinarian within minutes.

Get started
  • Low-cost video vet consultations, 24 hours a day Low-cost video vet consultations, 24 hours a day
  • Experienced, licensed vets Experienced, licensed vets
  • Over 700,000 satisfied pet owners Over 700,000 satisfied pet owners

Speak to a vet within minutes

4.9 On the App Store 3600+ reviews