Updated 11 February 2013


Captopril is the active ingredient of Capoten, Bio-Captopril, Capace, Captohexal, Captomax, Merck-Captopril, Sandoz Captopril and Zapto.


Captopril is the active ingredient of Capoten, Bio-Captopril, Capace, Captohexal, Captomax, Merck-Captopril, Sandoz Captopril and Zapto.

Captopril is also one of multiple active ingredients found in Capozide (Capoten + Hydrochlorothiazide), Captoretic (Capoten + Hydrochlorothiazide) and Zapto Co (Capoten + Hydrochlorothiazide).

General Information

Captopril is an angiotensin-converting enzyme (ACE) inhibitor prescribed for the treatment of high blood pressure and congestive heart failure, a condition where the heart battles to cope with its workload. It causes blood vessels to relax and widen, thereby reducing high blood pressure.

This medication is not a cure for high blood pressure, but is effective in keeping it under control. For it to be effective you must take it regularly. High blood pressure declines slowly and it may take a few weeks for captopril to reach it full effect. Keep taking this medicine during this period, even if you are feeling better, or fail to notice any improvement.

Captopril can be used on its own, or in combination with certain other medication for high blood pressure. It is often effectively combined with diuretics. In black patients captopril is significantly less effective if not prescribed together with a diuretic.

The first couple of doses of this medication may cause a sudden drop in blood pressure which may cause dizziness or blackouts when you suddenly get up. It is therefore advisable to be resting when starting treatment, and to lie down for 2 hours afterwards.

The use of captopril is often associated with a dry and persistent cough. Should you notice an irritating cough while being treated with this drug, it is advised to contact you doctor.

Captopril should be avoided during pregnancy, especially the second and third trimester. Speak to your doctor about the use of this drug if you are planning to get pregnant as it may cause harm to the unborn baby.

How does captopril work?

Captopril works by preventing the conversion of angiotensin I, a chemical in your blood, to a more powerful version, Angiotensin II. Angiotensin II has a narrowing effect on blood vessels, thereby increasing blood pressure. Angiotensin II furthermore stimulates the production aldosterone, a hormone which promotes salt (sodium) retention in the body, an action which increases blood pressure.

By inhibiting the forming of angiotensin II, captopril lowers blood pressure and thereby decreases the workload on the heart.

Fast facts

Drug schedule: Schedule 3

Available as: Captopril is available as tablets

What does it do? Captopril lowers high blood pressure and reduces the heart's workload.

Overdose risk: Medium

Dependence risk: Low

Is captopril available as a generic? Yes

Is captopril available on prescription only? Yes

User information

Onset of effect: Within 60 minutes

Duration of action: Up to 8 hours

Dietary advice: Take on an empty stomach 1 hour before food.

Stopping this medicine: Use captopril as prescribed by your doctor, and do not discontinue. treatment before speaking to your prescriber. Suddenly discontinuing the drug may case you blood pressure to increase dangerously. Dosage should be deceased gradually as directed by your doctor.

Prolonged use: No problems are expected. Your doctor may perform periodic tests of the blood and urine should the need arise.

Special precautions

Consult your doctor before using this drug if:

  • You have a kidney disease
  • You have a heart condition which your doctor is not aware of
  • You are allergic to ACE-inhibitor drugs
  • You are taking other medication
  • You are pregnant or planning to become pregnant.

Pregnancy: Avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.

Breastfeeding: Avoid. This medication is passed through breast milk and may affect your baby adversely. Consult your doctor before use.

Porphyria: Avoid. This medication may cause serious adverse effects. Consult your doctor before use.

Infants and children: This medication is not intended for use in children.

Elderly: Caution is advised in the elderly; a reduced dose may be needed

Driving and hazardous work: This medication should be avoided as it may cause extreme sedation.

Alcohol: Avoid concomitant use of alcohol with this medication.

Possible side effects

Side effect


Consult your doctor



Only if severe

In all cases

Loss of taste






Dry cough






Rash/ itch



Muscle weakness



Swelling of face, lips, tongue or throat



Swelling of arms and legs



Difficulty swallowing



Abdominal pain with/without nausea/vomiting




Drug interactions


Possible allergic reactions


Enhanced blood pressure lowering effect

Other medication for high blood pressure

Enhanced blood pressure lowering effect


Increased risk of potassium toxicity


Increased risk of digoxin toxicity


Increased lowering of blood pressure


Increased risk of lithium toxicity

Non-steroidal anti-inflammatory drugs

Effect on blood pressure is impaired

Potassium supplements

Increased risk of potassium toxicity


May increase blood pressure

Food interactions

Potassium-rich foods such as tomatoes and bananas

Disease interactions

Consult your doctor before using this drug if you have a kidney disease, a heart condition which your doctor is not aware of, or if you are allergic to ACE-inhibitor drugs.

Overdose action

A small overdose is no cause for concern. In case of intentional large overdose, seek emergency medical attention. Symptoms may include dizziness or fainting.

Recommended dosage

12.5 - 25 mg 2-3 times per day. Maximum dose of 150 mg/day.


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