ACE inhibitor (short-acting) Pregnancy: Not recommended in the first trimester; contraindicated in the second and third trimesters (fetotoxicity: decreased renal function, oligohydramnios, skull ossification retardation; neonatal renal failure, hypotension, hyperkalaemia). Breast-feeding not recommended for preterm infants or in the first few weeks after delivery.

Captopril

Brand names: Capoten

Captopril is a short-acting angiotensin-converting enzyme (ACE) inhibitor used in hypertension, heart failure, after myocardial infarction and in diabetic nephropathy.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Hypertension: 25–50 mg daily in two divided doses, increased at intervals of at least 2 weeks to 100–150 mg/day in two divided doses

Route: Oral

Frequency: twice daily (in divided doses)

Max: 150 mg daily

Dose individualised to blood pressure response. Strongly active renin-angiotensin-aldosterone system (hypovolaemia, renovascular hypertension, cardiac decompensation): commence with a single 6.25 mg or 12.5 mg dose under close supervision, twice daily, increased gradually to 50 mg/day then if necessary 100 mg/day. Heart failure: usual starting dose 6.25–12.5 mg twice or three times daily, titrated to maintenance 75–150 mg/day (max 150 mg/day). Myocardial infarction (short-term): 6.25 mg test dose, 12.5 mg at 2 hours, 25 mg at 12 hours, then 100 mg/day in two doses for 4 weeks; long-term cardioprotection 75–150 mg daily in two or three doses. Type I diabetic nephropathy: 50–100 mg daily in two or three divided doses. Elderly: consider lower starting dose (6.25 mg twice daily). Paediatric posology was truncated in the fetched label (a measuring guide lists 0.15 mg/kg and 0.3 mg/kg but no complete regimen was captured) — clinician to source paediatric dosing.

Dose adjustments

Renal

Reduce dose in renal impairment (based on creatinine clearance): CrCl >40 ml/min — start 25–50 mg, max 150 mg/day; 21–40 — start 25 mg, max 100 mg/day; 10–20 — start 12.5 mg, max 75 mg/day; <10 — start 6.25 mg, max 37.5 mg/day. A loop diuretic is preferred over a thiazide in severe renal impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to captopril, to any other ACE inhibitor or to any of the excipients
History of angioedema associated with previous ACE inhibitor therapy
Hereditary/idiopathic angioneurotic oedema
Second and third trimesters of pregnancy
Concomitant use with aliskiren-containing products in patients with diabetes mellitus or renal impairment (GFR <60 ml/min/1.73 m2)
Concomitant use with sacubitril/valsartan; must not be initiated earlier than 36 hours after the last dose of sacubitril/valsartan

Side effects

Dry, irritating (non-productive) cough and dyspnoea (common)
Taste impairment and dizziness (common)
Nausea, vomiting, gastric irritation, abdominal pain, diarrhoea, constipation, dry mouth (common)
Pruritus with or without rash, rash, alopecia (common)
Hypotension (uncommon); serious but less frequent: neutropenia/agranulocytosis and angioedema

Interactions

Aliskiren-containing products — contraindicated in diabetes mellitus or renal impairment (GFR <60)
Sacubitril/valsartan — contraindicated (increased risk of angioedema); 36-hour washout required
Diuretics / other vasodilators — increased risk of symptomatic hypotension; correct volume/sodium depletion and consider lower starting dose

Clinical monograph

How it works

It inhibits ACE, reducing the conversion of angiotensin I to angiotensin II and decreasing aldosterone secretion, producing vasodilatation and reduced sodium and water retention.

Prescribing in practice

Contraindicated in pregnancy due to the risk of fetal toxicity from drugs acting on the renin-angiotensin system.
Can cause hyperkalaemia, renal impairment and first-dose hypotension, with particular caution in volume depletion, renal artery stenosis and concomitant potassium-sparing agents.
May cause a persistent dry cough and, rarely, angioedema, which requires immediate discontinuation.

Monitoring

Monitor blood pressure, renal function and serum potassium before and after starting treatment and following dose changes.

Counselling the patient

Tell your prescriber immediately if you become pregnant, as this medicine must be stopped.
Report any swelling of the face, lips or throat urgently, and mention a persistent dry cough.

Evidence & guidelines

ACE inhibitors including captopril improve outcomes in heart failure and after myocardial infarction, as shown in landmark trials such as SAVE.

Reference: SmPC Capoten; NICE NG136 (Hypertension); NICE NG106 (Chronic HF); SAVE trial NEJM 1992; 327:669-77; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways