Intravenous nitroglycerin for the treatment of angina at rest unresponsive to standard nitrate therapy

Thirty-five patients who had angina at rest that was unresponsive to standard therapy comprised of oral or topical nitrates and beta-blocking drugs were treated with a continuous infusion of intravenous nitroglycerin (IVNTG). The infusion was started at 10 μg/min and increased by 10 μg/min increments every 5 minutes until an infusion rate of 50 μg/min was reached. After each episode of rest angina, the infusion was increased by 50 μg/min in the same stepwise manner. Data from a 24-hour baseline control period were compared with those from a 24-hour IVNTG endpoint period at which time the highest IVNTG infusion rate was administered. The average IVNTG infusion rate was 140 ± 15 μg/min. With IVNTG therapy, the number of episodes of angina at rest decreased from 3.5 ± 0.4 to 0.3 ± 0.1, sublingual nitroglycerin use decreased from 1.9 ± 0.3 to 0.4 ± 0.1 mg/day, and morphine sulfate administration decreased from 5.5 ± 1.3 to 0.4 ± 0.2 mg/day (all p <0.001). When each patient's response on the endpoint day was analyzed, 25 were defined as complete (no rest angina), 8 as partial (>50% decrease in the number of episodes/day from control values), and 2 as nonresponders. No significant drug-induced adverse effects occurred. IVNTG appears to be effective therapy for angina at rest refractory to standard oral and topical medications.