How much Benadryl can you give a dog?

From our video partners

Chemotherapy
Learn what to expect, and what can be done to improve the experience.

Benadryl For Dogs

Benadryl -- or diphenhydramine -- is a first-generation antihistamine. It has been around for a very long time, and it has survived the test of time well, often out-shining newer antihistamines with ease.

While it has some side-effects (pronounced drowsiness being the most common), diphenhydramine is extremely safe for most applications; and even better, most if not all of its interactions and side-effects are known. Note that it is counterindicated when your dog (or your human) has prostatic disease, hyperthyroidism or glaucoma.

There are other, less common interactions, that you can check via the Related Link below. It is very difficult to give a lethal dose of Benadryl. This most definitely does not mean it's okay to exceed dosing -- it's not. It does mean that you are not likely to accidentally kill your dog with a tiny mistake. Having been around so very long, diphenhydramine has a huge list of possible, super-rare, super-unlikely (and probably false) interactions.

For example, there's a mention of a fatality of a patient in class III FDA trials for daptomycin (a tricky, dangerous, powerful antibiotic) who also injested 650mg of diphenhydramine (10x the normal make dosage for humans, per USA standards). The patient's diagnosis as well as the reason that doctor choose that massive a dosage -- in other words everything that happened -- are excluded from the record. So there's a listed case of Benadryl interacting with daptomycin --- even though there's no indication that it actually had an effect. The reason I go into such detail is to illustrate that medications like diphenhydramine have a lot of history, some of it anecdotal.

It's a very safe med. My vet and others I've asked about this specifically say you should administer up to 1mg/lb every 8 hours (or 3 times a day -- tid). So if you have a 20 lb. dog, it's 20 mg of diphenhydramine. This is higher than the equivalent dose for humans, but nevertheless seems to be the accepted dose for dogs.

Benadryl Elixir. In America, Canada, and most countries that enact DUI laws, elixirs like Benadryl stopped using alcohol as part of the suspension many years ago. While I doubt you could find a bottle with alcohol in it today, it's still a good idea to always look at the label.

The only active ingredient should be diphenhydramine. As many medications that are sold OTC contain other meds, this really is a critical point. This means that Benadryl Decongestant, Benadryl for Colds, etc. are all unacceptable.

Benadryl can help with:

• Allegies/histaminic reactions -- in fact it can save lives, as well as stop itching from allergies.
• Hay Fever (Atopia -- another allergy -- this one airborne).
• Motion sickness and insomnia in dogs but not cats (note that it sometimes takes a long while to get un-drowsy).
• Bee and hornet stings.

Note that diphenhyramine is rarely adminstered for herpetoxins (snake bite). Common snake toxins are generally somatic or neurotoxic -- not histaminic (that would be spiders :} ). Administering diphenhydramine in the field to combat snake envenomation is an uncertain practice with unknown results, and should be avoided.

Diphenhydramine should be a part of everyone's first aid kit -- the human or dog one.

Note: When giving any med to humans or animals, it's strongly advised to get professional advice from your doc or your vet.

First answer by Bob95603. Last edit by Leahbird. Contributor trust: 2 [recommend contributor]. Question popularity: 104 [recommend question]