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Spironolactone

Why has my veterinarian prescribed this medicine?

Spironolactone is a diuretic, and is used to increase the amount of urine produced and excreted from the body. It is prescribed when the pet does not respond to other diuretics, or if other diuretics have resulted in low potassium levels.

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How do I give this medication?

  • Give this medicine to your pet as directed by your veterinarian. READ THE LABEL CAREFULLY.
  • DO NOT give your pet more medicine than directed
  • DO NOT give the drug more often than directed
  • Ensure your pet has access to clean drinking water at all times.
  • If the pet requires more than one dose a day, try to give the last dose by early evening, unless otherwise indicated by your veterinarian. This will minimize the number of times the cat needs to be let out at night.

What if I miss giving a dose?

Give the dose as soon as possible. If it is almost time for the next dose, skip the missed dose, and continue with the regular schedule. Do not give the pet two doses at once.

How do I store this medicine?

  • Keep this medicine out of reach of children
  • Store tablets and capsules in a cool, dry place at room temperature. Liquid medications should be kept in the refrigerator (2° to 8°C).
  • Do not store this medicine in the bathroom, near the kitchen sink or in damp places. The medicine may break down if exposed to heat or moisture.

What are the potential side effects?

  • This medication may cause stomach upset, which may lead to loss of appetite, vomiting and/or diarrhea. Contact your veterinarian if these symptoms persist or are troublesome.
  • The pet may urinate large amounts more often.
  • This medicine may cause some animals to feel tired or confused.
  • Other side effects may occur. If you notice anything unusual, contact your veterinarian.

Are there any possible drug interactions?

  • Make sure to tell your veterinarian what other medication you are giving to your pet.
  • Quite often, your veterinarian may prescribe two different medications, and sometimes a drug interaction may occur. In this case, your veterinarian may vary the dose and/or monitor your pet more closely.
  • Use spironolactone with caution when administering the following drugs: other potassium sparing diuretics, potassium supplements, indomethacin, ACE inhibitors, digoxin, aspirin, norepinephrine, other diuretics or antihypertensive agents. Food may enhance the absorption of spironolactone.
  • Contact your veterinarian if your pet experiences any unusual reactions when different medications are given together.

© Copyright 2025 LifeLearn Inc. Used and/or modified with permission under license. This content written by LifeLearn Animal Health (LifeLearn Inc.) is licensed to this practice for the personal use of our clients. Any copying, printing or further distribution is prohibited without the express written consent of LifeLearn. This content does not contain all available information for any referenced medications and has not been reviewed by the FDA Center for Veterinary Medicine, or Health Canada Veterinary Drugs Directorate. This content may help answer commonly asked questions, but is not a substitute for medical advice, or a proper consultation and/or clinical examination of your pet by a veterinarian. Please contact your veterinarian if you have any questions or concerns about your pet’s health. Last updated on Jul 8, 2016.