Cat Benadryl Dosage Calculator

Calculate the safe Benadryl (diphenhydramine) dosage for your cat. Get accurate dosing for allergy relief and other veterinary-approved uses. Always consult your vet before administering.

Your cat's weight in kilograms

Recommended Dose = 1 mg/kg body weight. Safe Range: 0.5-2 mg/kg. Frequency: Every 8-12 hours, maximum 2-3 times daily. Use ONLY plain diphenhydramine - avoid products with other active ingredients.
5kg (11 lbs) cat: Dose = 5 mg. Liquid form: 2 ml of 12.5mg/5ml solution. Tablet: 1/5 of 25mg tablet (use liquid instead). Give every 8-12 hours as needed, max 2-3x daily.

Is it safe to give my cat Benadryl?

Benadryl (diphenhydramine) can be safe for cats when used correctly under veterinary guidance. Typical dose: 1 mg/kg every 8-12 hours. CRITICAL: Use ONLY plain diphenhydramine. Many products contain decongestants, acetaminophen, or other ingredients that are TOXIC to cats. Always consult your vet before administering.

What is Benadryl used for in cats?

Veterinarians may recommend Benadryl for: Allergic reactions (mild), itching from allergies, insect bites/stings, motion sickness, mild anxiety, pre-medication before vaccinations. NOT for: Severe allergic reactions (anaphylaxis), respiratory distress, or chronic conditions without vet supervision. Consult vet for proper diagnosis and treatment plan.

How much Benadryl can I give my cat?

Standard dose: 1 mg per kg body weight (0.5 mg per pound), given every 8-12 hours. Safe range: 0.5-2 mg/kg. Example: 5kg (11 lb) cat = 5mg dose. Never exceed 2 mg/kg without vet approval. Overdose causes sedation, dry mouth, urinary retention, or more serious effects. Always verify dosing with your vet.

What form of Benadryl should I give my cat?

Best: Liquid children's formulation (12.5mg/5ml) - easier to dose accurately for small cats. Tablets (25mg): Can be split but difficult for small doses. AVOID: Capsules (hard to split), products with multiple active ingredients, any formulation containing phenylephrine, pseudoephedrine, acetaminophen, or ibuprofen - these are DEADLY to cats.

What are the side effects of Benadryl in cats?

Common: Drowsiness/sedation, dry mouth, urinary retention. Less common: Excitement/hyperactivity (paradoxical reaction in some cats), decreased appetite, vomiting, diarrhea. Serious (rare): Difficulty breathing, rapid heart rate, seizures. If you observe serious side effects or worsening symptoms, contact your vet immediately.

When should I NOT give my cat Benadryl?

Avoid if your cat has: Glaucoma, heart disease, high blood pressure, hyperthyroidism, urinary obstruction, pregnancy. Never use with: Other sedatives, MAO inhibitors, certain antidepressants. Never for: Severe allergic reactions (anaphylaxis) - requires emergency vet care. Always check with vet before giving Benadryl if cat has any health conditions or takes medications.