ACE inhibitors and angiotensin II receptor blockers
*ACE inhibitors (ACEi) and angiotensin II receptor blockers (ARB)* *Drugs* ACEi include enalapril, ramipril, and lisinopril. ARBs include losartan and candesartan. *Mechanism* 🎯Reduce levels (ACEi) or effects (ARB) of angiotensin II. 🎯Angiotensin II increases BP via systemic vasoconstriction, sodium retention, and aldosterone and ADH release. 🎯Lower efficacy in black patients, so not 1st line in this group. *Side effects* 🎯 _ACEi-specific:_ ➡️Dry cough (10%). Switch to ARB if occurs. ➡️Angio-oedema: rare (0.1%) but 3x commoner in black patients. 🎯 _ACEi and ARB:_ ➡️↑K+ due to ↓aldosterone. ➡️↓↓BP when starting, so start low and titrate. _Renal effects:_ ➡️Can impair renal function: ↓GFR via efferent dilation, especially dangerous in bilateral renal artery stenosis. ➡️However, it is often kidney protective via increased renal blood flow, so is used in chronic kidney disease and diabetes. ➡️↓GFR only occurs when efferent dilation outweighs the increased blood flow *Contraindications* _Absolute:_ 🎯K+ >5.5. 🎯Bilateral renal artery stenosis. However, used in unilateral disease. 🎯Pregnancy: causes cleft palate. _Cautions:_ 🎯K+ >5. 🎯Use ↓dose in kidney failure. *Management* Check K+ and creatinine at the following times: ☑️Baseline: 1 wk pre + post starting. ☑️After each dose increase. ☑️During severe illness, especially if dehydration risk. ☑️Routinely: annually, or more if ↓GFR. _Actions:_ ☑️If creatinine ↑20% from baseline or GFR ↓ 15%, recheck within 2 wks and if no better discuss with nephrologist. ☑️If K+ >5.5, reduce dose, if K+ >6, stop.
