Claritin for cats?
Q: We have two cats with feline herpesvirus. One becomes very congested overnight, sneezes up mucus clumps, and goes through intense coughing each morning. The other has sneezing fits. What is your opinion of using Claritin to help tamp down on symptoms, and what would be the weight-to-dose-ratio? We are asking because our daughter’s cat had seasonal allergies that caused her to sneeze and become congested, and her veterinarian put her on a partial tablet of Claritin to help clear the symptoms.
Karen and Stevan Adler
Gold Canyon, Arizona
Dear Mr. And Mrs. Adler,
A: We’re not surprised that both of your cats have feline herpesvirus (FHV). It is very contagious, which is why the American Association of Feline Practitioners considers the vaccine against this disease one of the “core vaccines.” Once the virus enters a cat’s body, it is there forever, and symptoms can periodically recur.
As for the use of Claritin to mitigate the respiratory symptoms of the disease, we could see why it might seem appropriate. The active ingredient of Claritin is an antihistamine (the generic name of the drug is loratadine), and over-the-counter antihistamines are sometimes administered to cats when they have upper respiratory infections. But antihistamines would not generally be considered a go-to in the case of FHV, even though that, too, is an upper respiratory infection.
Yes, there are instances in which veterinarians recommend it for FHV, but cats with that disease generally require more intensive care that includes subcutaneous fluid therapy, antimicrobial drugs for secondary bacterial infections that often accompany the virus, eye ointments (eye problems including conjunctivitis are common complications of the condition), humidifying treatments, and nutritional support. Severely affected cats may even require hospitalization (in isolation so they don’t infect other cats) and treatment with intravenous fluids and supplemental oxygen. An over-the-counter product like Claritin wouldn’t add much to the virus-fighting arsenal.
If your vet does recommend Claritin to ease your pets’ symptoms, please note that it is contraindicated for cats with kidney or liver disease. In fact, if a cat becomes unusually drowsy on an antihistamine, those diseases should be suspected, and the pet should be taken in for a work-up.
The form of the drug is critical, too. Cats should only take Claritin tablets, not the syrup. The syrup contains propylene glycol, which can cause a condition called Heinz body anemia that results in lethargy, loss of appetite, rapid heart rate, and other dangerous side effects. Cats should also not take Claritin-D or any other antihistamine that contains pseudoephedrine due to potential unpredictable adverse effects. Additionally, a cat should not be on Claritin long-term without a veterinarian’s say-so. As with any drug taken over the long run, monitoring is essential.
Finally, just like people, some cats respond better to certain antihistamine products than others. For certain cats, Benadryl might be the best symptom reducer. For others, an antihistamine specifically formulated for felines might work best. Tufts veterinary dermatologist Ramón Almela, DVM, often recommends Zyrtec (cetirizine) when an antihistamine is called for, say, in the case of seasonal allergies a cat might have. He notes that it has more of a track record, while there’s not a lot of experience with the use of loratadine in cats. (Again, only the tablet form should be used.)
If you do opt for Claritin or another over-the-counter antihistamine in tablet form with your vet’s say-so (they’re all “off-label” for cats, meaning not approved for that species by the FDA), you’re going to need a pill splitter. In the case of Claritin, for instance, your cats will require only a fraction of a 5-milligram tablet once a day; the doctor will tell you how much depending on the cats’ weight. If it’s Zyrtec that comes in 10-milligram tablets, you will need to split it in half to get the 5 milligrams generally recommended.
Finally, if you don’t see any improvement after one or two doses, stop. The drug is not going to suddenly “kick in” after that.
