Angioedema may occur especially following first dose with ACE inhibitors, involving the head and neck or the intestine. Cholestatic jaundice, which may progress to fulminant hepatic necrosis, may occur. A dry, hacking, and nonproductive cough may occur. Hyperkalemia may occur, mainly in relation to renal dysfunction, diabetes mellitus, concomitant use of potassium-sparing diuretics, potassium supplements and/or potassium-containing salts. Anaphylactic/anaphylactoid reactions can occur. Symptomatic hypotension with or without syncope can occur (more likely in volume-depleted patients). Patients with renal impairment (mainly those with associated collagen vascular disease (e.g. systemic lupus erythematosus)) are at higher risk of developing neutropenia. Deterioration of renal function and/or increases in serum creatinine may occur. In severe aortic stenosis it may reduce coronary perfusion resulting in ischemia. Blood pressure may fall in ischemic heart disease or cerebrovascular disease. Patients with collagen vascular disease may be at increased risk for hematologic toxicity (more frequent in renal impairment). In hypertrophic cardiomyopathy and outflow tract obstruction a reduction in afterload may worsen symptoms. Avoid use when unstented bilateral renal artery stenosis is present (elevated risk of deterioration in renal function). Use with caution before, during, or immediately after major surgery (use of ACE inhibitors perioperatively will blunt angiotensin II formation and may result in hypotension).