Effects of Long-Term Use of Amitriptyline in Cats

OK, I'll behave myself. I don't need those drugs any more.
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If your kitty develops bad behaviors, especially what is euphemistically referred to as "inappropriate elimination," your vet might prescribe medication to get him back on track. That includes the anti-depressant amitriptyline, marketed for people under the brand name Elavil.


Originally used to treat anxiety in humans, amitriptyline is now used by small animal vets to treat several conditions in cats and dogs. The drug increases the amount of the neurotransmitter serotonin in the body. Given once a day in pill form, amitriptyline doesn't necessarily have to be a long-term medication for the cat. Transdermal patches are also available. It takes at least a week, sometimes more, for the drug to begin working in the feline patient. Once the inappropriate behavior stops, you can wean your cat off the drug.

Uses in Cats

Besides inappropriate elimination, which means that the cat is pooping and peeing outside of the litter box, amitriptyline is also used in cats to treat separation anxiety, feline lower urinary tract disease and obsessive grooming. It's also prescribed for house cats who fight a lot, but whether it's the bully or the victim who receives the drug depends on the owner and vet's call. Because it also acts as an antihistamine, your vet might prescribe it if your cat has severe skin allergies, but it's not usually the first choice for skin issues.

Side Effects

Side effects of amitriptyline run the gamut, with some only affecting kitty for a short while while others have long-term effects. In a worst-case scenario, your cat can go into a coma or experience convulsions. More common side effects include both constipation and diarrhea, drooling, disorientation, sleepiness, weight gain, urinary retention, low blood pressure, changes in appetite, skin irritations, puffy face and heart rhythm changes. In other words, this is pretty serious medication. It should not be used in pregnant or lactating cats or in felines with diabetes.

Long-Term Effects

Used long-term, amitriptyline might effect major organs. One of the most common long-term side effects of amitriptyline regards the heart. For this reason, before the cat takes the medication, your vet should perform on EKG on her to make sure her heart's healthy. It may also suppress your cat's bone marrow, damage the kidneys and affect his liver. According to Dr. Wendy C. Brooks, "In humans, side effects in virtually every organ system have been reported at one time or another which means that potentially any side effect could be attributed to the use of this medication."

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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