Putting a Dog to Sleep with Benadryl

A dog owner’s best over-the-counter friend is without a doubt the antihistamine Benadryl! There are so many reasons to keep a stock of this medicine on hand for your dog, even if you don’t use it for yourself. It can help with allergies and even insect bites and stings, but did you know you can also use it for sedation? That’s right! Putting a dog to sleep with Benadryl is a pretty safe and easy way to make the side effects work for you.

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While it is best to talk to your veterinarian about putting a dog to sleep with Benadryl, this is one of those medications that is used frequently in dogs at home. It is a safe and effective way to treat minor allergic reactions, and it is a great way to help your pet stay calm when you don’t want to use a more powerful sedative.

Putting a Dog to Sleep with Benadryl

The recommended dose for Benadryl in dogs is 1 mg of Benadryl per pound, based on your dog’s weigh.  It is usually given when needed, up to three times a day.

The good news is that putting a dog to sleep with Benadryl has a pretty wide safety margin in its dosing recommendations for dogs!

The challenge is that the medication is usually sold in 25 mg tablets. So unless your dog weighs exactly 25 pounds (or 50, or 75 etc), you will likely have to divide a tablet to get the correct dose.

You might also want to read:  Benadryl Dosage for Dogs 

You don’t need to be too concerned about getting this division down to the milligram. For instance, if your dog weighs 14 pounds, you don’t need to try and divide a tablet into 16 sections in order to give them an exact dose of 14 mg’s. You can just give them half a tablet of Benadryl (a 12.5 pound dose) and call it close enough.

Avoid Using Benadryl on Dogs under 6 pounds

The exception to this loose dosing guide is for really small dogs, under 6 pounds. For these little guys, I would really recommend talking to your vet about the dose before using Benadryl at home. The chance of giving your dog too much Benadryl and causing unintended side effects is just too likely without guidance.

Think about it. A quarter tablet of Benadryl is the perfect dose for a 6.25 pound dog. It’s a little more than a 6 pound dogs needs, but still pretty close. But it is a lot more than a 5 pound dog should have!

The smaller the dog, the more likely they are to be negatively affected by giving the wrong dose.  Before putting a dog to sleep with Benadryl, it’s best to consider the dog’s size.

Some folks get around this by using a children’s formula and measuring out the correct dose with a syringe. This works well, but I still advise you to get your veterinarian to calculate the dose. The dosing guide below is intended for dogs over 6 pounds.

The following YouTube Video talks about Benadryl for Dogs

Benadryl Dose for Dogs

This guide is for dosing dogs from 6-25 pounds in weight, or for larger dogs who fall in between tablet sizes. So, for a 30 pound dog, you would give one full tablet (25 mg) and then another quarter tablet (6.25 mg).

It is safer to err on the side of not giving too much, rather than worry about underdosing. You can always give another dose in a few hours if needed. You may have to play around with the dose and find what works best for your dog.

Also, different circumstances can affect how your dog reacts to the medication.A smaller dose might work to put your dog to sleep on a quiet night, but have little effect on them during a fireworks show.

For 6-8.5 pound dogs, give ¼ of a tablet

For 8.6-12.5 pound dogs, give ½ tablet

For 12.6-19 pound dogs, give ¼ of a tablet along with ½ a tablet (¾ tablet total)

For 20-25 pound dogs, give 1 full tablet

How to Divide Tablets

The easiest way to divide Benadryl tablets is to use a pill splitter. You can get one online or from a pharmacist for a few dollars. It is much easier to split a tablet in half than in quarters.

One reason the pills are tough to split accurately is that they are coated with a layer of material that keeps the tablets from crushing against each other in the bottle. This layer often makes the tablets split unevenly, or worse, causes them to crush when quartering.

The man on this youtube video talks about antihistamines for sleep

I admit that when I was working in veterinary medicine, I usually avoided the pill splitters and used a surgical blade to divide tablets instead. It was more accurate and was easier to avoid accidentally crushing the tablets. I have tried using a kitchen knife for this at home, and it has never worked well for me. If you have a very sharp, thin blade (think boning knife), it might work for you.

Another option is to use a kitchen scale to weigh the Benadryl pieces, if you have one that is accurate for measurements of 1 milligram.

For most dogs, this shouldn’t be a big problem. The dose doesn’t need to be precise, so there’s no reason to sweat over slightly uneven fractions.


You can safely use Benadryl to put your dog to sleep! Just follow the dosing guide, and always talk to your vet if you have any questions or concerns!


Jen Clifford has a B.A. in Biology from Reed College. She was a field biologist for several years and then spent 10 years working in veterinary medicine as a receptionist and technician.  Jen is currently a freelance writer living in the Pacific Northwest with her tribe of pets. She is a passionate animal lover who is dedicated to helping people find solutions to their pet-related challenges. You can find more of her work on her website https://MyWickedTribe.com.