Veterinarian-written / veterinarian-approved articles for your cat.

Feline Pharmaceuticals Part I

cat_with_vetAll the lotions, potions, and weird looking pills on the shelves. Do you ever wonder just a bit about the medicine your veterinarian is prescribing but were afraid to ask? Here is a quick look at some of the medications used by veterinarians:


This is a very large group of medicines, and one of the most likely your pet will be prescribed over their lifetime, at one time or another. These medications do not treat infections caused by viruses or fungi—just those caused by bacteria.

Over the years, resistant strains of bacteria have arisen by mutation so that great care must be exercised in their use. This adaptation by bacteria is a natural phenomenon, but one which we try to discourage. We can help reduce the emergence of new resistant bacteria by administering all of the medication which has been dispensed, according to the prescribed schedule.

Giving only part of a prescription or giving the medicine at irregular intervals can encourage resistant germs to grow. Avoid flushing any outdated antibiotic down the toilet as it ends up in rivers and lakes and can affect wildlife. Instead, return any old medicines to the veterinary hospital for proper disposal.

Some antibiotics can treat classes of different bacteria (broad spectrum) while others effectively target only one or a few specific types of bacteria (narrow spectrum). Some of the antibiotics we prescribe are not specifically labeled for use in cats, and your veterinarian will advise you in that case. The drug companies cannot afford to do licensing trials in all of the minor animal species, so veterinary specialists and learning institutions carefully do trials, and once that has happened and results are published, the general practitioner will often adopt these newer “off-label” drugs if they have shown potential.

Some frequently noted side effects with oral antibiotic administration include vomiting and diarrhea. Stomach upset may be reduced by feeding the cat at the time of the drug administration. Allergic reactions are rare, and if you suspect a serious reaction, take your cat to the hospital immediately. With treatment, the reaction usually subsides quickly.

Cats don’t cherish taking their medications generally, and antibiotics are no exception. Some antibiotics are very bitter, and if you crush the pill to try to give it as a powder, this may trigger profuse drooling and some dark looks. Only break pills open if advised to do so by your pet’s doctor.


As the name implies, these types of medicines help reduce inflammation. They have other effects in the body as well—some desirable, some not so. Some also have quite powerful anti-fever (antipyretic) effects and can also be very effective pain killers (analgesics).

Non-steroidal anti-inflammatory (NSAID)

This subset of medicines is very popular for home treatments for people. Aspirin, acetaminophen, ibuprofen, ketoprofen, and others are common in the household first aid cabinet. Unfortunately, cats lack the enzyme system in their liver to effectively process this type of medication, so as a group they are considered unsafe to give to cats. The rare exception is the prescription use of children’s dosage of aspirin at very long dose intervals for limited applications such as feline embolism prevention. A few other NSAIDs are also considered safe for one-time administration only, under veterinary supervision in order to control surgical pain. None of these, including aspirin should EVER be selected for care of cats at home since the consequences can be serious or life-threatening. If a cat accidentally gets into any of these drugs, an immediate trip to the vet hospital is in order.


These are also anti-inflammatory drugs, but of a different class. Another word for them is glucocorticoids. If you know of people and dogs that have been prescribed prednisone, prednisolone, or other common steroid preparations, you will know that in these species, side effects are common. Side effects also occur in cats, but cats do seem to be a bit more tolerant of this type of medication. Increased thirst, weight gain, and increased urinations are common side effects. If high or long-term doses are given, or doses are not tapered, other more serious effects including diabetes mellitus can potentially develop. Long-term use can lead to changes in skin and liver, and at high doses, the immune system is suppressed so an increased susceptibility to infection occurs.

In spite of all these concerns, these drugs do play a key role in the management of certain diseases of cats and can help improve quality of life in some situations.

Creams and Ointments

Many types of medication are delivered topically. Cats hate any creams or ointments. They are so fastidious that as soon as you apply it, they take it off unless physically restrained from reaching the area. For this reason, unless topicals are used with protective bandaging or head cones that prevent grooming an area, topical treatments are a tough sell to cats.

A cream is a water-soluble based preparation, while an ointment is an oily base. Both can work to hold antibiotics or steroids or natural compounds in suspension so that they are held against the skin. Some new medications are delivered trans-dermally using special vehicles that permit enhanced absorption through the skin. One painkiller called fentanyl can be delivered via a patch attached to the shaved skin, but it is important the cat not be able to get at it and chew it up.

See Pharmacy Part II for more information on drugs such as fluids, digestive disorder products, hormone replacement or inhibition products, anti-viral, cancer and immune system modulators, heart and blood pressure products, and bronchodilators.

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