Safety of intravenous nitroglycerin after administration of sildenafil citrate to men with coronary artery disease: a double-blind, placebo-controlled, randomized, crossover trial

OBJECTIVE: Although contraindicated, there are situations when a patient who has recently taken a phosphodiesterase 5 inhibitor (e.g., sildenafil) might need intravenous nitroglycerin (NTG) treatment. This study determined if, and at what dose, intravenous NTG could be administered safely to men with coronary artery disease who had recently ingested sildenafil. DESIGN: Double-blind, placebo-controlled, randomized, crossover trial. SETTING: Four clinical practice sites in Canada, Scotland, and the United States. PATIENTS: A total of 34 men (>or=35 yrs) with a history of angina pectoris and coronary artery disease (>50% stenosis of at least one coronary artery), most of whom were taking antihypertensives. INTERVENTIONS: Sildenafil (100 mg) or placebo (single dose; crossover after 3-7 days) followed 45 mins later by escalating doses of intravenous NTG (160 microg/min maximum). MEASUREMENTS AND MAIN RESULTS: After sildenafil, there were slightly greater maximum (supine) blood pressure decreases and heart rate increases (e.g., 4 to 6 mm Hg [systolic] and