Sulfite sensitivity especially in patient w/ asthma. Continuously monitor ECG, BP, pulmonary wedge pressure, cardiac output & serum K. Avoid bolus administration. Hypovolemia should be corrected prior to use. Concomitant use w/ β-blockers. Marked mechanical obstruction eg, severe valvular aortic stenosis; hypokalemia; known subclinical or overt DM. Do not add to alkaline soln eg, Na bicarbonate. Pregnancy. Childn & elderly.