Angiotension converting enzyme (ACE) inhibitors

Angiotension converting enzyme (ACE) inhibitors:
Inhibits conversion of angiotensin I to angiotensin II. Angiotensin II is a potent vasoconstrictor and stimulator of aldosterone release (aldosterone increases retention of sodium and water  increase in blood volume and increase in peripheral resistance). Blocking synthesis of angiotensin II  decrease in blood pressure from reduced vasoconstriction and decrease in afterload from net water loss (from less aldosterone secretion)

Commonly used when beta-blockers and/or diuretics are ineffective.

eg Captopril, Fosinopril, Enalapril, Lisinopril, Perindopril, Quinapril, Ramipril, benazepril
• indicated for hypertension, heart failure, myocardial infarction
• inhibit ACE  inhibits production of angiotensin II  removes influence of angiotensin II  vasodilation (arterioles > venules) and reduction of blood volume (by acting in kidneys)
• have little or no effect on cardiac output
• most effective when hypertension is result of increased levels of renin

Adverse effects:
Renal failure, cough, fatigue, headache, diarrhoea, skin rashes, angioedema, hypotension (high risk on first dose), hyperkalaemia (due to inhibition of ADH)