Erythrityl tetranitrate compared with isosorbide dinitrate. Effects on systolic time intervals and nitrate modification of effects of food.

The pharmacologic effects of erythrityl tetranitrate (ETN) and isosorbide dinitrate (ISDN) were compared to placebo using systolic time intervals (STI) in a randomized, double-blind study in 15 fasted male volunteers. Sublingual doses of ETN 5 mg, ISDN 5 mg, and placebo were administered to each volunteer at weekly intervals, and measurements of heart rate and STI [pre-ejection period (PEP), left ventricular ejection time (LVET), and PEP/LVET ratio] were made serially for up to 6 hours after each dose. STI were determined using ear densitography. Evaluation of the pharmacologic effects of ETN and ISDN were based on placebo-corrected changes from baseline values. Ejection time index (ETI) [LVET corrected for heart rate] was shortened, but the changes were not statistically significant for either drug. However, after ETN and ISDN, statistically significant (p less than 0.05) changes in PEP and PEP/LVET ratio were demonstrated for up to 240 minutes after dosing. Unexpected marked changes in the baseline corrected PEP/LVET ratio were observed following food at 4 hours after dosing. This suggests increased inotropy during the postprandial period.