PetMD Editorial
By PetMD Editorial on Nov. 7, 2012

Drug Info

  • Common Name: Capoten®
  • Drug Type: ACE inhibitor
  • Used For: Heart failure, High blood pressure
  • Species: Dogs, Cats
  • Administered: Tablets
  • How Dispensed: Prescription only
  • Available Forms: Capoten® 12.5mg, 25mg, 50mg, and 100mg tablets
  • FDA Approved: No

General Description

Captopril is used to treat minor to severe heart failure and high blood pressure. It lowers blood pressure, lowers the stress on the heart, and reduces fluid build-up in the lungs. It is often used in conjunction with other drugs.

It is best to give this drug on an empty stomach. If stopping use of this drug, consult your veterinarian for an effective gradual reduction in dosage.

How It Works

Captopril inhibits the angiotensin converting enzyme (ACE), an enzyme that converts angiotensin I to angiotensin II. Angiotensin II acts as a potent vasoconstrictor, meaning it narrows the blood vessels. By inhibiting this enzyme, it prevents the angiotensin II from ever being created and relaxes the blood vessels. This lowers the blood pressure and reduces the amount of work the heart has to do.

Storage Information

Store in a tightly sealed container at room temperature.

Missed Dose?

If you miss 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 your pet two doses at once.


Side Effects and Drug Reactions

Captopril may result in these side effects:

  • Low blood pressure
  • Loss of appetite
  • Vomiting
  • Diarrhea
  • Rash
  • High blood pressure if medication is halted abruptly

Captopril may react with these drugs:

  • Antacids
  • Diuretics
  • Rimadyl (and other non-steroidal anti-inflammatory drugs)
  • Potassium sparing diuretics
  • Vasodilators
  • Cimetidine
  • Digoxin
  • Potassium chloride or gluconate

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