A Phase I, double-blind, randomized, crossover study in healthy males (N=106) was conducted between March 21, 2004, and May 17, 2004, to determine the magnitude and duration of the hemodynamic interaction of avanafil (a phosphodiesterase type-5 inhibitor for treating males with erectile dysfunction) when coadministered with glyceryl trinitrate (NTG) compared with sildenafil and placebo. Subjects received avanafil (200 mg), sildenafil (100 mg), and placebo (on separate days) via the oral route followed by NTG (0.4 mg) 12, 8, 4, 1, or 0.5 hours post-dose via the sublingual route. Blood pressure (BP) and heart rate (HR) were assessed at defined intervals.
Throughout the study (after administration of the study drug, and including the period after NTG administration), the effects of avanafil and sildenafil on BP and HR were significantly greatest overall, at the shortest (0.5-hour) time interval compared with placebo. By the 8- and 12-hour time intervals, no significant difference in BP or HR was observed for avanafil (8 and 12 hours) or sildenafil (12 hours) (p>0.05, compared with placebo). Compared with avanafil, sildenafil had a significantly greater effect when dosed 0.5 hours before NTG on standing HR (p=0.05); 1 hour before NTG on standing systolic blood pressure (SBP) (p<0.05), sitting SBP (p=0.01) and standing HR (p<0.01); and 12 hours before NTG on standing SBP (p=0.05). Throughout the study, symptomatic hypotension adverse events occurred in 27%, 29%, and 12%, and clinically significant reductions in standing SBP (≥30 mmHg) occurred in 15%, 29%, and 12% of subjects dosed with avanafil, sildenafil, and placebo, respectively (overall treatment differences: p<0.01 and p<0.05, respectively).
These data show that avanafil and sildenafil have no significant effect on BP and HR if administered to healthy males ≥8 hours (avanafil) or ≥12 hours (sildenafil) before a sublingual dose of NTG. However, results may differ in populations with known vascular disease, especially those using other concurrent pharmacotherapy. These findings may be of interest to clinicians who treat patients with erectile dysfunction and who also have a cardiovascular condition. Of note, the applicability of these results in such patients may be limited because the enrollment comprised healthy, normal subjects.