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Benadryl For Dogs: Dosage, Uses & Safety

12/12/2017 by Colleen Williams
December 12th, 2017 by Colleen Williams



Vet-approved for home use, Benadryl is a regular go-to treatment for allergies, motion sickness and anxiety in our pets. Benadryl is a relatively safe and effective medication for both cats and dogs, but there is a caveat! Your safest bet is to check in with your pet’s veterinarian first, especially if there are any other conditions or symptoms present.

What is Benadryl and how does it work?

Benadryl is a brand name for an antihistamine (diphenhydramine HCl) that can help alleviate allergic reactions, itching or even anxiety. Benadryl is not yet FDA-approved for veterinary use, but it is generally considered safe for use in dogs with mild-to-moderate allergies. Seasonal allergies, food allergies, environmental allergies and allergic reactions to insect bites all can be immediately treated with Benadryl. Symptoms of allergic reactions that can be treated with Benadryl include hives, swelling, itching. Severe reactions, like anaphylaxis, can be life-threatening and should be treated by a veterinarian (who may give an injection of diphenhydramine along with other emergency injections).

“Benadryl is widely available over the counter and can be used under the advice of your veterinarian for mild itching from allergies, insect bites, flea irritation and a number of other conditions,” says Dr. Justin Shmalberg, DVM and veterinarian nutritionist at NomNomNow. “It’s a very safe medication; it may cause drowsiness in some pets but my clients have never found this to occur at a concerning level.  Of course, if a problem persists, if there are open sores or if you notice any adverse reactions to this medication, talk to your veterinarian as soon as possible.”

Because Benadryl also causes drowsiness, pet parents have also had luck with using the medication to help calm their anxious dog. The Merck Veterinary Manual also approves of using Benadryl to help relieve motion sickness during car rides.

Dosage of Benadryl for Dogs

“The usual dosage is about 1 mg per pound, two to three times daily. I often have people start with a half dose to see how much it sedates the dog the first time around,” Dr. Shmalberg says. The doctor also goes on to note, “The tablets and capsules commonly come in 25mg size, but pet parents should be aware that other sizes exist (like 50 mg).”

Dr. Shmalberg recommends the following with a 25mg tablet:

Very Small Dogs (4-10 pounds): 1/4 tablet
Small Dogs (10-20 pounds): 1/2 tablet
Medium Dogs (20-30 pounds): 1 tablet
Larger dogs: 1 tablet per 25 pounds body weight

Give your own vet a quick call before dosing your dog; they may recommend bringing your pup in first for a visit. If you administer Benadryl without first consulting your veterinarian, watch your dog for any further symptoms or if his/her condition worsens.

Possible Side Effects

If your dog or cat has any chronic conditions like glaucoma, diabetes, epilepsy or seizures, consult your vet before dosing your pet as some of these conditions can worsen with the addition of the drug. The most common side effects include sedation, dry mouth, urinary retention and rapid breathing. The rarest of side effects include diarrhea and vomiting.

Allergies were the 8th most frequent reason for dog parents visiting the vet last year, according to the 2017 Cost of Pet Health Care report. Protect your pet and your wallet by signing up for pet health insurance while they’re still young. Start by getting a free quote.




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