Angioedema may occur (especially following 1^st^ dose); may involve head and neck (potentially compromising airway) or intestine (presenting with abdominal pain). Blacks and patients with idiopathic or hereditary angioedema may be at increased risk. Use in previous angioedema associated with ACEI therapy contraindicated. Anaphylactic/anaphylactoid reactions can occur with ACEIs. Cholestatic jaundice, which may progress to fulminant hepatic necrosis may occur. A dry, hacking, nonproductive cough usually occurs within first few months of treatment and should generally resolve within 1-4 weeks after discontinuation of ACEI. Hyperkalemia may occur with ACEIs (higher risk if renal dysfunction, diabetes mellitus, concomitant use of potassium-sparing diuretics, potassium supplements, and/or potassium-containing salts). Symptomatic hypotension with or without syncope can occur with ACEIs (usually with the first several doses). Another ACEI, captopril, associated with rare cases of agranulocytosis, neutropenia, or leukopenia with myeloid hypoplasia (higher risk of developing neutropenia if renal impairment or renal impairment and collagen vascular disease). Renal function deterioration may be associated with increases in serum creatinine, particularly in low renal blood flow (e.g. renal artery stenosis, heart failure) with glomerular filtration rate dependent on efferent arteriolar vasoconstriction by angiotensin II. Use with caution in severe aortic stenosis (may reduce coronary perfusion resulting in ischemia), in hypertrophic cardiomyopathy and outflow tract obstruction (reduction in afterload may worsen symptoms associated with this condition), and in unstented unilateral/bilateral renal artery stenosis (use generally avoided due to elevated risk of deterioration in renal function). ACEIs can cause injury and death to developing fetus when used in 2^nd^ and 3^rd^ trimesters (ACEIs should be discontinued as soon as possible once pregnancy is detected). Use with caution before, during, or immediately after major surgery (cardiopulmonary bypass, intraoperative blood loss, or vasodilating anesthesia increases endogenous renin release).