Benadryl for Cats: Benefits, Safety, Dosage and More!

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By: CertaPet Staff Updated: April 20, 2021

benadryl for cats

We all like to think of our pet pals as part of the family, so when they suffer from health problems, it’s the worst! Many pet parents go into panic mode when their dogs and cats show symptoms of illness and immediately rush to the vet. Is there something we already have in the medicine cabinet that could help them? Maybe! People often turn to human meds like Benadryl for dogs, but Benadryl for Cats?

Often we have a wide range of human drugs in the house that can also help our furry friends, without even knowing it. One of those drugs is humble Benadryl, which can be used to assist pets with allergic symptoms, and more. In this article, we explore how you can use Benadryl for cats to help your feline to be feline fine in no time!

What is Benadryl?

Benadryl is actually the brand name of an antihistamine drug which is known as diphenhydramine. Diphenhydramine is sold as one of the over-the-counter medications that pharmacists recommend to assist with symptoms of allergies, such as sneezing, a runny nose, watery eyes, rashes, hives, skin itching, and other cold or allergy symptoms.

While Benadryl is a well-known brand of diphenhydramine, you can also purchase this medication in the generic form. Generic Benadryl is generally less costly than the brand name drug but is the same quality. Ask your pharmacist about the generic option to save money on medicating your pet.

Is Benadryl Safe: Can You Give a Cat Benadryl? Can Cats Take Benadryl? 

If your cat has an allergic reaction to something or just allergies in general, it is safe to give them Benadryl or diphenhydramine.

However, a number of factors MUST be discussed with a veterinarian prior to administering the drug. The amount and suitability of Benadryl for cats in terms of administration depend on a number of things.

The first variable is the reason for giving Benadryl to cats. If the situation is more severe, for example, a large amount of swelling due to a bee sting, this will affect the amount of Benadryl for cats to be given.

Other factors that come into whether Benadryl for cats is safe are:

  • Age of the cat
  • Size of the cat
  • Other underlying medical conditions
  • Any other medications the cat is on
  • Other allergies the cat may have

Ensure that you discuss and disclose all this information to your vet so that they can give you the best advice on whether Benadryl is safe for your cat. Some of the factors listed above, such as age, can affect the safety of Benadryl for your cat hugely! IF your vet is fully informed they can give you the safest and most effective information about using Benadryl for cats.

Remember what appears to be cat allergies could be something else, so if you suspect something is not right, visit your vet for an assessment.

cat sneezing

Kitten Sneezing? Mother Nature Knows Best: Natural Relief for Allergies in Cats!

If your cat cannot tolerate Benadryl or diphenhydramine medication for any reason, there are other natural options for antihistamine relief from allergies.

One of the best natural remedies for supporting skin health and assisting the immune system in cats is CBD oil.

How Honest Paws CBD Oil Can Help Your Cat!

CBD oil is a plant-based supplement that can support a healthy immune system and promote skin health.

Honest Paws CBD oil contains cannabidiol or CBD, which is sourced from farms in Colorado. CBD is a chemical compound from the cannabis plant that is known to support skin health while also assisting the immune system.


Benadryl for Cats: What it Does and How it Works!

So how does Benadryl for cats, aka diphenhydramine, work on our little kitty’s system?

Benadryl is an antihistamine, which regulates the amount of histamine produced in the body. When a human or animal comes into contact with allergens from the environment, the body reacts by producing histamines which cause symptoms like inflammation and itchiness in response.

The drug diphenhydramine blocks the H-1 receptors, which are found on the small blood vessels and smooth muscles. When histamines attach to these receptors, they cause the blood vessels to swell and widen, which causes swelling, inflammation and an itchy skin.

Those with allergies of their own can sympathize with poor pusses suffering from allergies or an allergic reaction – histamines make it an uncomfortable and unpleasant experience!

Queasy Cat? What About Benadryl for Nausea?

Apart from relief from allergy symptoms, diphenhydramine or Benadryl also has some other nifty uses in pets. For dogs, Benadryl is an excellent drug to help with motion sickness, when taken in consultation with a veterinarian.

If your cat suffers from motion sickness when riding in your car, Benadryl for cats is an option, as it can work as a mild sedative. This can help relax your kitty and get them to sleep through a traumatic car trip.

Be aware! This sedative effect can be dangerous for older cats.

Benadryl for cats can be effective in treating nausea, but vets say that if that is the main symptom you are treating it’s best to go with a specific drug for that.

cat allergies

How Long Does Benadryl Take to Work?

Benadryl for cats, aka diphenhydramine, is a fast-acting drug. It usually takes effect within 30 minutes of dosage.

How Long Does Benadryl Last for Your Lil’ Kitty?

The active ingredient in Benadryl for cats, diphenhydramine, can have long-lasting effects. Benadryl for cats generally lasts between 8-12 hours.

Understanding Benadryl Half-Life 

As with all chemical substances, diphenhydramine has a recorded half-life. The half-life of a drug is the time that it takes for half of the active ingredient – in this case, diphenhydramine, to be eliminated by the body.

Tests have measured the half-life of Benadryl to be from 3.4 and 9.3 hours in adult humans, with a median figure of 4.3 hours. Half-life in our furry friends is slightly longer due to the slower rate with which their smaller bodies break down Benadryl.

Benadryl Dosage for Cats

Correct Benadryl dosage for cats is extremely important, as an overdose can be dangerous and even fatal. When giving Benadryl to cats for a number of symptoms and complaints such as a cat bee sting, insect bites, itchy skin or another allergic reaction, it’s essential to consult your veterinarian to work out their dose.

The dosage of Benadryl for cats is probably easiest to control precisely when given in liquid form. Liquid measurement can be given precisely to the milliliter depending on the cat’s size.

See your vet to work out a perfect dosage plan for your cat.

NEVER follow the instructions on a pack of Benadryl for cats – these are for humans only!

Tablets, Liquid Benadryl and Spray: Which is Best for Cats?

For a precise dose, liquid Benadryl for cats is best. It is also simple to disguise the liquid form of Benadryl in your cat’s food or drink for the fussiest purring prince or princess.

Tablets are also an option but it can be more difficult to get the correct dosage right. The bonus of tablets is they can be easily crushed and hidden in food, and are less messy than trying to get Benadryl liquid in your kitty’s mouth.

Another option is Benadryl spray, which is especially effective in treating skin conditions. Used topically directly on rashes, it can soothe itching in cats.

Potential Side Effects to Look Out for!

Benadryl for cats is safe at the correct dosage as determined by your vet, but it can have some side effects. Some common side effects in cats include:

  • Hyperexcitability in cats
  • Dry mouth, with can cause a foaming mouth
  • Decrease in urination
  • Sedation
  • Vomiting
  • Diarrhea
  • Loss of appetite

If these side effects continue after the Benadryl should have worn off, see your doctor.

medicine for cat allergies

Signs and Symptoms an Overdose or Allergic Reaction

Cats that are given an overdose of Benadryl or are allergic to the medication can have serious reactions that need vet attention immediately. Some of the signs that your cat has overdosed on Benadryl or is allergic to the drug are:

  • Mild fatigue
  • Clumsiness
  • Shortness of breath
  • Seizures

If your cat has a reaction like this, seek medical assistance immediately.

Where Can I Buy It? 

So where is the best place to buy Benadryl for pet owners? Online stores like Amazon make it quick and easy to have the medication sent wherever you live. Otherwise, you can buy Benadryl for cats or generic diphenhydramine at any reputable drugstore.

Our animals are our furry babies, so it’s no wonder we freak out when they’re not feeling well! Being educated on the medicines you already have at home to treat them is an invaluable way to make sure your animal loved ones are happy and healthy.

With consultation with your vet, you can treat them from the safety and comfort of home. If you have a cat that suffers from symptoms that can be alleviated by Benadryl, try it at home today.

Disclaimer: This post may contain references to products from one or more of our partnered sites, Honest Paws and Vets Preferred. However, CertaPet content is to be used for educational and informational purposes only. Please seek veterinary advice for your own situation. For more on our terms of use, visit this page

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