Inhibit ACE → ↓ AT II → ↓ GFR by preventing constriction of efferent arterioles. ↑ renin due to loss of negative feedback. Inhibition of ACE also prevents inactivation of bradykinin, a potent vasodilator.

Use:- Hypertension- HF (↓ mortality)- Proteinuria- Diabetic nephropathy- Prevent unfavorable heart remodeling as a result of chronic hypertension.- In chronic kidney disease (eg, diabetic nephropathy), ↓ intraglomerular pressure, slowing GBM thickening.

Adverse effects:- Cough and angioedema (both due to ↑ bradykinin; contraindicated in C1 esterase inhibitor deficiency)- Teratogen (fatal renal malformations)- ↑ creatinine (↓ GFR)- Hyperkalemia- Hypotension- Used with caution in bilateral renal artery stenosis because ACE inhibitors will further ↓ GFR → renal failure.