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Helping a Dog Sleep with Benadryl

Helping a dog sleep with Benadryl is one use of this over-the-counter drug. Benadryl is used to treat a variety of allergies.

The drug, in fact, is effective in treating everything from mild allergies to snake bites. Drowsiness is actually a side-effect of the medication.

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. In some situations, helping a dog sleep with Benadryl is a useful application.

While it is best to talk to your veterinarian about helping a dog 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.

This post is for informational purposes only. It is not designed to provide medical advice. Please consult a veterinarian before administering any drugs (over-the-counter, prescription, herbal remedies, etc.) to your dog.

Benign is safe for dogs in certain circumstances infographic.

Best Products for Anxiety

Sometimes, helping a dog sleep with Benadryl is useful for long trips or during times when you know your dog is going to be a little overwhelmed.

Whether you have guests coming for a few nights or you’re about to embark on a long road trip, the routine change can make your dog pretty nervous.

If you follow the dosing guidelines (below) and make sure not to overdo it (don’t give too much!), there’s a chance that Benadryl is all you’ll need.

If your dog is particularly nervous and won’t settle down, there are other things to consider.

If you have a nervous dog, consider trying a Mellow Shirt Dog Anxiety Calming Wrap combined with Natural Calming Treats for Dogs. One size does not fit all so be sure to shop around for the best size, fit, and comfort for your pooch.

This is What I Do For MY Dogs

My dogs are quite large at roughly 80 pounds each, and when they get nervous it’s really hard to get them to calm down.

My pit mix, Coco, has learned to soothe himself by climbing into the tub when he’s nervous or unsettled. My other dog, a golden retriever, just shakes and comes to me for soothing.

My solution won’t work for every dog, but I’ve found simply giving them each a soft teddy bear to carry around does wonders.

Don’t get me wrong…it won’t work when fireworks are lighting up the sky. However, if they’re just having a little anxiety, the bear-trick works great.

The teddy bears seem to be a great source of comfort for them, unlike any of the other toys they have around the house.

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.

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 attempting to help a dog 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.

Benadryl Dose for Dogs

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.

Benadryl has a pretty wide safety margin; however, it’s not designed to be used long-term without a licensed veterinarian’s approval.

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.

Don’t worry if the dosage isn’t precise, just use common sense. It’s not always easy to split a dose, so as long as you’re in the ballpark, your dog should be fine.

Remember, don’t just take my advice for it. Give the veterinarian a call and get some over-the-phone guidance on the best dosage for putting a dog to sleep with Benadryl.

It’s better to give too little a dosage than too much. Never give your dog more than the recommended dosage. Higher dosages can increase the risk of side-effects.

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.

Other Side-Effects of Benadryl for Dogs

The medical ingredient in Benadryl is known as Diphenhydramine HCL, a compound found in other antihistamines used both for humans and animals.

Antihistamines like Benadryl do come with a variety of side-effects however. Luckily, most of them are usually mild.

Your dog may experience the following side-effects when administered Benadryl:


As mentioned above, this is probably what you want, especially if you need your pooch to rest and take it easy. The calming effect can help your dog sleep better and be less anxious for a period of time.

Dry Mouth

It’s not unusual for dogs taking antihistamines to develop a dry mouth. You might notice your dog licking his/her lips more often or the top lip kind of sticking to the gums because of the dryness.

As a result of the dry mouth, your dog may drink more water in an attempt to solve the problem.

Vomiting and/or Diarrhea

Generally speaking, helping a dog sleep with Benadryl isn’t something you do over the long term.

The occasional dose of Benadryl isn’t likely going to produce noticeable side-effects like the ones mentioned here.

However, if your dog seems to be having any kind of a reaction to the drug, make sure to contact the veterinarian for advice.

Do not give Benadryl to dogs under 6 months of age infographic.

Bone UP on Dog Medications

The following guide should give you a pretty good idea of how much Benadryl to give your dog, especially if you’re looking to help him/her sleep or ease mild anxiety.

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

There are a ton of great products on the market, including books that help guide loving dog-owners on what medications are available for dogs, dosing guides, side-effects to expect, etc.

There are plenty of reasons to want to keep your dog calm, including the period of time right after surgery when your dog really needs to rest.

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.

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.


Other options to help calm your dog involve drug-free options like the Thunder Dog Anxiety Jacket combined with specially formulated calming treats or even plush toys. With a little thought, I’m sure you will find the best combination of therapies just right for your dog. After all….who knows him/her better than you?


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.

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