(Aldactone® is another name for this medication.) 

Use: Spironolactone is a diuretic that is used in patients who don’t respond to other diuretics or who have developed a low potassium from other diuretics.

Side Effects: Spironolactone can cause high levels of potassium in the blood. If your animal becomes weak or lethargic (lacking energy) while on spironolactone, you should call your veterinarian. Spironolactone can cause loss of sodium from the blood and make your animal weak or confused. If you notice these signs, call your veterinarian. As spironolactone is a diuretic, it can cause too much water loss and your pet can become dehydrated. Make sure your pet has access to plenty of fresh, clean drinking water at all times. Some animals will get stomach upset (vomiting and diarrhea) from spironolactone.

Precautions: Spironolactone inactivates the drug called mitotane which is used to treat Cushing’s disease in dogs. You should not give spironolactone to a dog that is being treated with mitotane. Spironolactone causes the body to save potassium. It should not be used in animals that already have too much potassium or where increased potassium levels could cause problems (Addison’s disease, diabetes).

Directions: Spironolactone should be given orally once to twice daily. Your veterinarian may instruct a pharmacist to compound a special oral liquid; this is good for 30 days when stored in the refrigerator. Specially compounded oral liquids of spironolactone should be shaken well, stored in the refrigerator, and discarded after 30 days.

Remember: Spironolactone should be stored in a tight, light resistant, childproof container away from all children and other household pets.

If you miss a dose of this medication you should give it as soon as you remember it, but if it is within a few hours of the regularly scheduled dose, wait and give it at the regular time. Do not double a dose as this can be toxic to your pet.