Diltiazem reduces the dose requirement for nitroprusside-induced hypotension

The efficacy of diltiazem, a calcium channel blocker, for reducing the dose requirement for nitroprusside-induced hypotension was studied in 20 healthy patients during spine fusion for scoliosis. Anesthesia included methohexital (3 mg/kg followed by 3 mg.kg -1 .h -1 intravenously), nitrous oxide, and alfentanil (40 μg/kg, followed by 0.7 μg.kg -1 .min -1 intravenously). Patients were assigned randomly to two groups, receiving either nitroprusside alone or nitroprusside and diltiazem (bolus of 80 μg/kg with two consecutive infusions of 4.5 μg.kg -1 .min -1 during the first 30 min and then 1.3 μg.kg -1 min -1 ). Nitroprusside was used to maintain mean arterial pressure at 55-60 mm Hg in both groups