Skip to main content

Captopril

Why has my veterinarian prescribed this medicine?

Captopril is an angiotensin-converting-enzyme inhibitor (ACE inhibitor) that is used to lower blood pressure and to improve heart function.

How do I give this medication?captopril-1

"If you are allergic to sulfa drugs, handle this medication cautiously."
  • Give this medication to your pet as directed by your veterinarian. READ THE LABEL CAREFULLY.
  • If the medicine is a liquid, measure the dose with reasonable care.
  • Try to give this medication at about the same time(s) each day.
  • Give this medication on an empty stomach, 1 hour before meal(s) unless otherwise directed by your veterinarian.
  • DO NOT give the pet more medicine than directed.
  • DO NOT give the medicine more often than directed.
  • Try not to miss giving any doses. .
  • DO NOT stop giving this medication to your pet without first consulting the veterinarian. Call your veterinarian ahead of time if your pet requires refills of the medication.
  • If you are allergic to sulfa drugs, handle this medication cautiously.

What do I do 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 this medicine in a cool, dry place at room temperature below 300C. Store away from heat and direct sunlight.
  • 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?

  • Notify your veterinarian if your pet is very tired, weak or has difficulty rising.
  • In rare cases, skin rashes or neutropenia (a lower number of neutrophils, a specific type of white blood cell) have been reported.
  • Other side effects may occur. If you notice anything unusual, contact your veterinarian.

Are there any possible drug interactions?

"If your pet needs to take captopril and an antacid, separate the administration of the two medicines by at least two hours."
  • Make sure to tell your veterinarian what other medication you are giving to your pet.
  • Quite often, your veterinarian may prescribe two different medications, even if a drug interaction may occur. In this case, your veterinarian may vary the dose and/or monitor your pet more closely.
  • The following drugs can potentially interact with captopril: diuretics, other vasodilators, potassium or potassium sparing diuretics (e.g. spironolactone), digoxin, non-steroidal anti-inflammatory agents, probenecid, and cimetidine.
  • If your pet needs to take captopril and an antacid, separate the administration of the two medicines by at least two hours.
  • 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.