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

Feline Pharmaceuticals Part II


Another frequently used pharmacy item is intravenous or subcutaneous fluids. Fluids is a broad term used to describe solutions of varying compositions that can help replace body fluids, minerals, vitamins, and electrolytes lost due to lack of intake of food and water, bleeding, vomiting and diarrhea, burns, and kidney, or multi-system disease.

We normally talk about IV’s when we refer to fluids administered into veins. Fluids are sometimes given by other routes in special circumstances such as in tiny kittens that have small, fragile vessels, or when veins are collapsed due to severely low blood pressure. SC fluids are given under the skin. Not all fluids can be given by the SC route. Sometimes SC fluids are prescribed to be given at home to help maintain normal hydration in cats with chronic kidney failure.

Common fluid types are replacement formulations that are designed to replenish specific blood component deficiencies such as potassium, magnesium and calcium, and replace a volume of lost blood water. Others are rich in glucose to help cats with low blood sugar (hypoglycemia) to normalize. The other fluid type is termed maintenance formulation. These are used to maintain the normal blood volume and balance once a patient is stabilized, but is not yet drinking normally. Sometimes, vitamins or drugs are added to the fluid line to provide therapy or special nutritional support.

Sometimes in veterinary medicine, oral electrolyte solutions are selected to help replace fluid loss, but cats tend not to take them with anything approaching enthusiasm.

Digestive Disorder Products

Products to treat digestive system disorders are many, and varied. Severe constipation may be treated with an enema product, but human drugs like Fleet ® enemas are very toxic to cats, so enema products should only be used under veterinary supervision. Lubricating products may be used to help deal with hairballs or low grade constipation. Many of these hairball gels come in a tube with yummy caramel or tuna flavor and vitamins mixed into them. Constipated cats, especially seniors, may need to be given a fiber supplement to help keep them regular. Some diets have higher fiber to bulk up the diet, while other times a specific fiber supplement is added such as psyllium or pumpkin. Another approach is to use stool softeners that help to increase the water content of the stool, or laxatives that stimulate the guts to move the contents along.

Diarrhea may be treated with protectants, anti-parasitic, motility modifiers, antibiotic, or anti-inflammatory medications depending on the cause. If food allergy is suspected, a prescription hypoallergenic diet may be considered. Sometimes appetite stimulants, nutritional supplements, and other adjunctive treatments are prescribed.

Vomiting and nausea may be treated with antiemetics to help soothe the signals that stimulate the vomit reflex.

Hormone Replacement or Inhibition

Diabetes mellitus may result from a shortage of functional insulin hormone, and sometimes insulin injections are prescribed to normalize blood sugar levels. Animal sources of insulin exist, and sometimes human recombinant insulin is used. Cats tend to require the longer acting preparations of insulin. This is a potent drug and your veterinarian will demonstrate how to properly store the medication, how to gently mix the vial, and administer the precise dose under the skin. If overdose of insulin occurs, the blood sugar can drop severely leading to sleepiness, or even seizures. Rubbing corn syrup on the gums can help to maintain a cat during transport to the hospital for stabilization. Diet may be adjusted also to help reduce blood sugar swings. Oral hypoglycemic agents and special prescription diets with high protein and low carbohydrate content may be used.

During hyperthyroidism, excess thyroid hormones are produced and sometimes drugs are used to stabilize the cat. The medication does not fix the underlying problem—only surgery or radiation therapy can remove the overactive tissues and fix the condition. Instead, this type of medication helps to prevent the hormones from affecting the tissues and this helps to reduce the signs of the disease.

Anti-viral, Cancer, and Immune Modulator Medications

These drugs are used where chronic retrovirus disease or cancers have lead to serious illness. Some of these preparations are quite toxic and powerful, and are handled and administered with care. Cats may require close monitoring when being treated with this sort of medication. Low white cell count, and malaise may occur with some of these treatments. Often, treatments are given over a period of time and a mixture of drugs given to help reduce side effects.

Heart and Blood Pressure Drugs

There are a number of drugs that are used to stabilize cats in heart failure or cats with cardiomyopathy of different types. The stage of heart failure will determine which drugs are selected for therapy. The dose of these powerful drugs needs to be titrated very carefully to minimize toxicity, so your veterinarian may need to closely monitor your cat during initial dosing.

Some drugs affect the ability of the heart muscle to contract, others have an effect on the heart rate or the capacity of the overall system by relaxing the blood vessel walls, while others affect the rhythm control system in order to control arrhythmias. Sometimes, drugs to help clear fluid build-up (diuretics) are added to the mix.


Cats with asthma may be prescribed medications to help relax the airways and reduce inflammation as part of management. These drugs may be delivered in a tablet form, or some of the human “puffer” medications may be delivered via a pediatric chamber.

Many other drugs are available in the modern veterinary pharmacy, but these are some of the most commonly prescribed. If you have any questions about a medication prescribed for YOUR pet, make sure you get them answered. Safe and effective use of medications dispensed for home use is very important.

See Feline Pharmaceuticals Part I for more information on commonly prescribed drugs.

You May Also Like These Articles:

Human Medications That Are Dangerous to Cats

Warning: Topical Medications Containing Flurbiprofen May Be Dangerous to Cats

How To Administer Medication to Your Cat

Common Cat Medications

Feline Pharmaceuticals Part I

Disclaimer: This website is not intended to replace professional consultation, diagnosis, or treatment by a licensed veterinarian. If you require any veterinary related advice, contact your veterinarian promptly. Information at is exclusively of a general reference nature. Do not disregard veterinary advice or delay treatment as a result of accessing information at this site. Just Answer is an external service not affiliated with

Notice: Ask-a-Vet is an affiliated service for those who wish to speak with a veterinary professional about their pet's specific condition. Initially, a bot will ask questions to determine the general nature of your concern. Then, you will be transferred to a human. There is a charge for the service if you choose to connect to a veterinarian. Ask-a-Vet is not manned by the staff or owners of, and the advice given should not delay or replace a visit to your veterinarian.