Can You Give a Cat Benadryl?

When you have an allergic reaction, it’s easy to just pop a Benadryl to ease your symptoms. Many dogs are given Benadryl to help them fend off allergic reactions. But is this drug safe for cats too?

 “It is safe,” says John Faught, a DVM and medical director of the Firehouse Animal Health Center in Austin, Texas. “Benadryl is just an antihistamine, and it's relatively safe for both dogs and cats.”

Benadryl is the brand name for the drug. The active ingredient is diphenhydramine, which you also can buy if you’re looking for a generic form of the medication. The Benadryl you’d get at the vet’s office is the same drug you’d buy off the shelf at your local grocery store.

How to Give Benadryl to a Cat

The easiest way to dose a cat is to syringe liquid Benadryl, says Faught. But many cats will simply refuse to take it if they don’t like the odor or taste. If your cat won’t take it, you can try going through a compounding pharmacy where the staff can flavor the liquid with chicken, fish or another cat-approved taste, which may increase the chance of your feline taking it. Pills also can be flavored, if you’d prefer to give the medication that way instead. You also could try to mix it up with their food to see if they’ll consume it with the meal.

Faught says his office doses Benadryl at about one milligram per pound. For an average sized cat, you’ll probably want to give half of a 25-milligram tablet. A 10-pound cat will most likely need about four milliliters of liquid (available at a concentration of 12.5mg/5ml) to get the right dose, he says.

What is Benadryl Used for in Cats?

Benadryl is most commonly used for itchy or allergic skin reactions, vaccine reactions or bug bites. Occasionally, the drug can work as a mild sedative that you can use during long car trips. Benadryl can be used as an anti-nausea or motion sickness medication, but Faught cautions that it’s best to use a different medication if that’s the symptom you’re trying to treat.

Precautions to Take When Giving Benadryl to Cats

Just like in people, Benadryl can cause a wide range of symptoms. Your cat may act drowsy. The drug, sometimes, may also cause a cat to get amped up or hyper. Overdoses can lead to seizures, coma, difficulties breathing, and even death.

As with giving any new medication, it’s best to talk it over with your vet to see if Benadryl might be right for your cat and ensure that the dosage won’t interfere with any other medications your cat may be taking.

It’s also best to ensure that the medication is not masking a larger issue, says Faught.

“Oftentimes, you can have mites or infection or something else that's going on that might be the underlying component,” he says. “Benadryl treats a symptom; it doesn't necessarily take away an underlying problem.”

If your cat is having a severe allergic reaction—with problems such as trouble breathing—it’s best to contact your vet to discuss the issue instead of just giving Benadryl to see if the symptom disappears.