What is Spironolactone?

How it works:
Spironolactone inhibits the effect of aldosterone, a hormone that causes the tubules of the kidneys to retain sodium and water. This increases the excretion of water and sodium, while decreasing the excretion of potassium.

Cautions:
Tell your veterinarian if your pet has kidney or liver disease, diabetes mellitus, high levels of potassium in the blood, or if your pet is being given a potassium supplement or an ACE inhibitor such as enalapril or lisinopril. Tell your veterinarian if your pet is pregnant or lactating.

Spironolactone will cause your pet to urinate more often, and your pet may have more "accidents" and need to go outside or use the litter box more. Make sure that your pet eats and drinks well while taking spironolactone or the risk of side effects increases.

What is the most important information I should know about Spironolactone: Spironolactone is a prescription medication that is not FDA approved for use in animals; however, it is a commonly accepted practice for veterinarians to use spironolactone in dogs and cats. Spironolactone is available as 25mg scored tablets. The usual dose in dogs and cats is 0.5-1mg per pound every 12 hours. Give spironolactone with food to lessen stomach upset.

What is Spironolactone: Spironolactone is a potassium-sparing diuretic (water pill). Spironolactone is used to reduce the amount of fluid in the body without also causing a loss of potassium. Spironolactone is used in the treatment of CHF, edema and high blood pressure (hypertension). Spironolactone is also used to treat potassium deficiency and hyperaldosteronism. Spironolactone may also be used for purposes other than those listed in this guide.

What should I discuss with my veterinarian before giving spironolactone to my pet: Tell your veterinarian if your pet has kidney or liver disease, diabetes mellitus, high levels of potassium in the blood, or if the pet is being given a potassium supplement or an ACE inhibitor such as enalapril or lisinopril. Tell your veterinarian if your pet is pregnant or lactating.

How should this medication be given: Give this medication exactly as directed by your veterinarian. If you do not understand the directions ask the pharmacist or veterinarian to explain them to you. Spironolactone should be taken with food to lessen stomach upset. Keep plenty of water available for your pet. Do not suddenly stop giving this medication. Stopping suddenly could make the condition worse. Store spironolactone at room temperature, away from moisture and heat. Keep this medication away from children and pets. 

What happens if I miss giving a dose: Give the missed dose as soon as you remember. However, if is almost time for the next regularly scheduled dose, skip the missed dose and take the next one as directed. Do not give a double dose of the medication.

What happens if I overdose the pet: Seek emergency veterinary medical treatment. Symptoms of spironolactone overdose include an irregular heartbeat, lethargy, fatigue, weakness, drowsiness, dizziness, confusion, shortness of breath, nausea and vomiting.

What should I avoid while giving Spironolactone to my pet: Do not use supplements containing potassium as these could cause high levels of potassium in the body.

What are the possible side effects of Spironolactone: If any of the following serious side effects occur, stop giving spironolactone and seek emergency veterinary medical attention; an allergic reaction (difficulty breathing; swelling of the lips; tongue or face; hives); an irregular heartbeat, shortness of breath, fatigue, confusion, weakness, numbness, or decreased urination. Other less serious side effects may occur. Continue giving spironolactone and talk to your veterinarian if your pet experiences headache, dizziness, nausea, diarrhea, decreased appetite, or dry mouth. Other side effects may also occur. Talk to your veterinarian about any side effect that seems unusual or bothersome to the animal.

What other drugs will affect Spironolactone: Tell your veterinarian if your pet is being given probenecid, a nonsteroidal anti-inflammatory (NSAID) such as etodolac, carprofen or piroxicam or a diabetes medication such as glipizide. You should also tell your veterinarian if your pet is taking any other medication to treat high blood pressure, edema, heart problems, or some other condition. Drugs other than those listed here may also interact with spironolactone. Talk to your veterinarian before giving your pet any prescription or over the counter medicines.

Where can I get more information: Your pharmacist has additional information about Spironolactone written for health professionals that you may read.