Angioedema may occur rarely with ACEIs, and may involve head and neck or intestine (use in previous angioedema associated with ACEI therapy contraindicated). Rare toxicity associated with ACEIs includes cholestatic jaundice, may progress to fulminant hepatic necrosis. Dry, hacking, nonproductive cough might occur, usually within first few months of treatment. Hyperkalemia may occur (risk factors include renal dysfunction, diabetes mellitus, concomitant use of potassium-sparing diuretics, potassium supplements, and/or potassium-containing salts). Anaphylactic or anaphylactoid reactions can occur. Symptomatic hypotension with or without syncope can occur. Patients with renal impairment are at high risk of developing neutropenia. Patients with both renal impairment and collagen vascular disease (e.g. systemic lupus erythematosus) are at even higher risk of developing neutropenia. May be associated with deterioration of renal function and/or increases in serum creatinine. Use with caution in severe aortic stenosis (may reduce coronary perfusion resulting in ischemia), in cardiovascular disease, in collagen vascular disease especially with concomitant renal impairment (may be at increased risk for hematologic toxicity), in hypertrophic cardiomyopathy and outflow tract obstruction (reduction in afterload may worsen symptoms), in unstented unilateral/bilateral renal artery stenosis, and in pre-existing renal insufficiency. ACEIs can cause injury and death to developing fetus when used in 2^nd^ and 3^rd^ trimesters. Use of ACEIs perioperatively will blunt angiotensin II formation and may result in hypotension.