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What is captopril?

Captopril (also called Capoten®) is an antihypertensive (drug that lowers blood pressure) known as an ACE inhibitor. It controls blood pressure by relaxing blood vessels. High blood pressure levels can damage kidneys and may lead to a stroke or heart failure. Captopril is available as a 25-mg tablet and as a 1 mg/mL liquid, both of which are taken by mouth.

Possible side effects of captopril

  • Feeling dizzy or light-headed, fainting spells
  • Cough
  • Low blood pressure
  • Decreased renal (kidney) function and less urine passed
  • Feeling tired
  • Low blood counts with higher risk of infection, bleeding, and anemia
  • High potassium blood levels
  • Headache
  • Swelling of face, lips, or tongue
  • Problems breathing or problems swallowing
  • Hoarseness or tightening of throat
  • Swelling of legs or ankles
  • Rash

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call the doctor, nurse or pharmacist at 595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833), and press 0 once the call is connected.

Special instructions for captopril

  • Stop taking captopril and tell your doctor right away if you have any of these problems:
    • Your face, lips, or tongue become swollen
    • Your voice becomes hoarse or your throat feels tight
    • You have problems swallowing or breathing
  • This medicine may cause you to feel dizzy or lightheaded. Do not operate heavy equipment or drive a motor vehicle until you see how this medicine will affect you. To avoid dizzy or fainting spells do not sit up or stand up too quickly.
  • You or your nurse should check your blood pressure regularly while you are taking captopril. Your doctor will tell you what to do if your blood pressure level is low or high. Your dose of captopril may change based on your blood pressure level. Call your doctor right away if your blood pressure is above _____________ or below_____________.
  • If you have a sudden onset of severe diarrhea or vomiting or if you sweat a lot, tell your doctor right away. This loss of body fluid may decrease your blood pressure.
  • Captopril may affect the way some medicines work. Some medicines may also affect the way captopril works. These medicines include ibuprofen or naproxen, heparin, lithium, potassium salts, and diuretics, including potassium-sparing diuretics. Always tell your doctor if you are taking any of these medicines, or if you start taking any new medicine while you are taking captopril.
  • Do not take salt substitutes or potassium supplements, or eat foods high in potassium while taking captopril.
  • Do not treat yourself for symptoms like cough, cold, or pain while you are taking captopril. Talk to your doctor before taking any medicine for these symptoms.
  • If the St. Jude pharmacy makes an oral liquid suspension of captopril, you should shake the suspension well before taking the medicine. The liquid should be refrigerated. Discard the medicine after the expiration date on the label.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).