Quinapril with hydrochlorothiazide

How it works

Quinapril inhibits angiotensin-converting enzyme to lower angiotensin-II-mediated vasoconstriction and aldosterone secretion, while hydrochlorothiazide increases renal sodium and water excretion; the ACE inhibitor offsets diuretic-induced renin-angiotensin activation.

Prescribing in practice

• Avoid in pregnancy because the ACE-inhibitor component is foetotoxic; counsel women of childbearing potential and review contraception.
• ACE inhibitors can cause angioedema requiring permanent withdrawal and a persistent dry cough, while the thiazide adds risks of hyponatraemia, hypokalaemia, hyperuricaemia and glucose intolerance.
• First-dose hypotension, hyperkalaemia and renal impairment can occur, especially with volume depletion, renal artery stenosis or NSAIDs.

Monitoring

Monitor blood pressure, renal function and serum electrolytes including sodium and potassium at baseline and after dose changes.

Counselling the patient

• Seek urgent help for swelling of the face, lips, tongue or throat.
• Report a persistent dry cough so an alternative can be considered.
• Tell your doctor immediately if you become pregnant.

Evidence & guidelines

Combining an ACE inhibitor with a thiazide diuretic is an established step in NICE hypertension management, and the fixed-dose combination supports adherence.