- Check Creatininine and Potassium within 2 weeks of initiation, then periodically 
ACE inhibitors are pharmacological agents that are commonly used for congestive heart failure and proteinuric states (especially diabetic nephropathy). Unlike other drugs, ACE inhibitors do not exacerbate insulin resistance or hyperlipidemia.
Absolute contraindications include pregnancy, previous edema due to ACE inhibition, and renal artery stenosis. Relative contraindications include kidney failure, or hyperkalemia. Side effects include cough, angioneurotic edema, hyperkalemia or renal insufficiency.
In cases of heart failure, ACE inhibitors are used for NYHA class II & III patients, and result in significantly lower (28%) mortality than hydralazine patients, though there is significant loss with continued follow-up. The mechanism is due totally to the reduction of cardiac sudden death and not to any vasodilating effect, suggesting an added effect of ACE inhibition.
Though this does not represent a huge component of the mechanism of ACE inhibitors, there is a vasodilating effect that also reduces afterload. Also, ACE inhibitors work through the prevention of myocardial hypertrophy and remodelling, which is thought to be a major protective mechanism.