Benadryl Dosage Calculator for Dogs
Calculate safe Benadryl (Diphenhydramine) dosage for dogs based on weight and formulation
Important Veterinary Notice
Always consult your veterinarian before giving Benadryl to your dog. This calculator provides general guidelines only and cannot replace professional veterinary advice.
Calculate Benadryl Dosage
Use your dog's current accurate weight
Select the Benadryl formulation you have available
Dosage Results
Dog Weight: 0 lbs (0.0 lbs)
Formulation: Liquid Benadryl (12.5 mg/5 mL)
Dosage Rate: 1 mg per 1 lb (2.2 mg per kg)
Frequency: Every 8-12 hours (2-3 times daily)
Dosing Schedule
Frequency: Give every 8-12 hours (2-3 times per day)
Maximum: Do not exceed 3 doses in 24 hours
Duration: Do not use for more than a few days without vet approval
⚠️ Do NOT Give Benadryl If Your Dog Has:
Pregnant dogs
Dogs with low blood pressure
Dogs with severe cardiovascular disease
Dogs with glaucoma
Dogs under 1 year old (consult vet first)
Dogs currently taking other medications
👁️ Watch for These Side Effects:
Lethargy or drowsiness
Dry mouth
Urinary retention
Vomiting
Diarrhea
Loss of appetite
Hyperactivity (paradoxical reaction)
Difficulty breathing (seek immediate help)
Emergency: If your dog shows difficulty breathing, excessive vomiting, or unusual behavior, contact your veterinarian or emergency animal hospital immediately.
Example Calculation
25 lb Dog with Flight Anxiety
Dog: 25 lb mixed breed, traveling by plane
Formulation: Liquid Benadryl (12.5 mg/5 mL)
Step 1: Calculate mg needed: 25 lbs × 1 mg/lb = 25 mg
Step 2: Convert to mL: 12.5 mg/5 mL = 2.5 mg/mL
Step 3: Amount needed: 25 mg ÷ 2.5 mg/mL = 10 mL
Result: Give 10 mL of liquid Benadryl
50 lb Dog with Allergic Reaction
Weight: 50 lbs → Dosage: 50 mg Benadryl
Options: 2 × 25mg tablets OR 4 × 12.5mg chewables OR 20 mL liquid
Important: Consult vet for severe allergic reactions
Common Uses for Benadryl
Allergic reactions (food, environmental)
Insect bites and stings
Motion sickness during travel
Anxiety from thunderstorms or fireworks
Mild skin irritation and itching
Pre-treatment for vaccine reactions
Formulation Guide
Liquid (12.5 mg/5 mL)
Most common, easiest to dose accurately
2.5 mg per mL concentration
Chewable (12.5 mg)
Good for small to medium dogs
Children's formulation
Tablets (25-50 mg)
For larger dogs, may need splitting
Adult formulation
Important Notes
Check ingredients - avoid combination formulas
Give with food to reduce stomach upset
Ensure fresh water is always available
Keep vet contact info readily available
Record dose time and your dog's response
Understanding Benadryl for Dogs
What is Benadryl?
Benadryl (Diphenhydramine) is an antihistamine that blocks histamine receptors, reducing allergic reactions and providing sedative effects. It's commonly used in veterinary medicine for various conditions.
How Does It Work?
- •Blocks histamine release from mast cells
- •Reduces inflammation and itching
- •Provides mild sedation for anxiety
- •Helps prevent motion sickness
Dosage Formula
Dosage = 1 mg per 1 lb body weight
OR 2.2 mg per 1 kg body weight
Generic Names
- Diphenhydramine (active ingredient)
- Brand names: Benadryl, Unisom, Sominex
- Other names: Genahist, ZzzQuil, Nytol
⚠️ Warning: Only use products containing ONLY diphenhydramine. Avoid combination medications that may contain harmful ingredients like acetaminophen, pseudoephedrine, or xylitol.