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 |
Frequency |
Consult your doctor |
Common |
Rare |
Only if severe |
In all cases |
Loss of taste |
x |
|
x |
|
Headache |
x |
|
x |
|
Dry cough |
x |
|
|
x |
Dizziness |
|
x |
x |
|
Rash/ itch |
|
x |
|
x |
Muscle weakness |
|
x |
|
x |
Swelling of face, lips, tongue or throat |
|
x |
|
x |
Swelling of arms and legs |
|
x |
|
x |
Difficulty swallowing |
|
x |
|
x |
Abdominal pain with/without nausea/vomiting |
|
x |
|
x |
Interactions
Drug interactions
Allopurinol |
Possible allergic reactions |
Anaesthetics |
Enhanced blood pressure lowering effect |
Other medication for high blood pressure |
Enhanced blood pressure lowering effect |
Ciclosporin |
Increased risk of potassium toxicity |
Digoxin |
Increased risk of digoxin toxicity |
Diuretics |
Increased lowering of blood pressure |
Lithium |
Increased risk of lithium toxicity |
Non-steroidal anti-inflammatory drugs |
Effect on blood pressure is impaired |
Potassium supplements |
Increased risk of potassium toxicity |
Rifampicin |
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.