Lisinopril with hydrochlorothiazide

How it works

Lisinopril inhibits angiotensin-converting enzyme to reduce angiotensin-II-mediated vasoconstriction and aldosterone secretion, while hydrochlorothiazide increases renal sodium and water excretion; the combination lowers blood pressure through complementary mechanisms.

Prescribing in practice

• The combination is contraindicated in pregnancy and in patients with previous ACE-inhibitor-associated angioedema, and the ACE inhibitor component should be stopped if angioedema occurs.
• Combining an ACE inhibitor with a thiazide affects potassium in opposing directions and can also cause hyponatraemia, so electrolytes need monitoring rather than being assumed to balance out.
• There is a risk of first-dose or volume-depletion hypotension, and hydrochlorothiazide carries cautions around gout, photosensitivity and a small increased non-melanoma skin cancer risk.

Monitoring

Monitor renal function, serum sodium and potassium and blood pressure before treatment and after initiation or any dose change.

Counselling the patient

• Seek emergency help if your face, lips, tongue or throat swell or you have difficulty breathing.
• Do not use this medicine in pregnancy; tell your doctor immediately if you become pregnant.
• Use sun protection and report dizziness, cramps or a dry cough.

Evidence & guidelines

Combining an ACE inhibitor with a thiazide diuretic for hypertension uncontrolled on monotherapy is consistent with NICE hypertension guidance and established combination-therapy evidence.