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Dose by weight

Benadryl Dosage for a 50 lb Dog

A 50 lb (22.7 kg) dog usually gets about 50 mg of diphenhydramine per dose, every 8 to 12 hours. The safe range is 45.4 to 90.7 mg. Adjust the calculator if your dog's exact weight is different.

What do you have at home?

Only use plain diphenhydramine. Never give "Benadryl-D", cold-and-flu or "plus" versions, and check liquids for xylitol, which is poisonous to dogs.

Usual vet dose

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Safe range (2 to 4 mg/kg)
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How often
Every 8 to 12 h

Talk to your vet first. This calculator uses the standard veterinary dose for diphenhydramine (2 to 4 mg per kg every 8 to 12 hours, Merck Veterinary Manual). It cannot know your dog's health history. Dogs with glaucoma, heart disease, high blood pressure, seizures, prostate or thyroid problems, pregnant dogs and dogs on other medicines may need a different plan. If your dog has face swelling, hives with breathing trouble, or collapses, go to an emergency vet now. Do not wait for Benadryl to work.

50 lb dog: Benadryl amounts by product

ProductUsual dose for 50 lb
Diphenhydramine in mg50 mg (range 45.4 to 90.7 mg)
Adult tablet, 25 mg2 tablets
Children's chewable, 12.5 mg4 chewables
Children's liquid, 12.5 mg per 5 mL20 mL

50 lb is a medium dog, about the size of a Pit Bull or Husky. Regular 25 mg tablets are the simplest option at this size. Split them along the score line if you need a half.

How often can a 50 lb dog have Benadryl?

Every 8 to 12 hours, so no more than 3 doses in 24 hours. If one dose doesn't seem to help, don't double the next one. Call your vet instead, because the problem may need a different medicine.

Watch for these side effects

Expect some sleepiness. Call your vet if your dog becomes very agitated, pants hard, has a racing heart, can't pee, or vomits repeatedly. Wide pupils, tremors or seizures can signal an overdose. If you see them, call ASPCA Animal Poison Control on (888) 426-4435 or go to an emergency clinic.

Always confirm the dose with your own vet, especially if your dog has a health condition or takes other medicines.

Frequently asked questions

How many mg of Benadryl can a 50 lb dog have?

About 50 mg per dose is the usual starting dose (roughly 1 mg per pound). The vet range for a 50 lb dog is 45.4 to 90.7 mg, no more often than every 8 hours.

How many 25 mg Benadryl tablets for a 50 lb dog?

About 2 tablets, which is 50 mg.

How much liquid Benadryl for a 50 lb dog?

About 20 mL of children's diphenhydramine liquid (12.5 mg per 5 mL). Use an oral syringe and make sure the product contains no xylitol.

Sources

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