Effects of STENDRA on Erectile Response

In a single-blind, placebo-controlled, single-dose trial of 82 patients with either organic and/or psychogenic ED, visual sexual stimulation resulted in improved erections after STENDRA administration compared to placebo, as assessed by an objective measurement of hardness and duration of erections (RigiScan®). Efficacy was assessed by RigiScan at discrete time intervals ranging from 20 – 40 minutes after dosing to 100 – 120 minutes after dosing. 

Effects of STENDRA on Blood Pressure

Single oral doses of STENDRA (200 mg) administered to healthy male volunteers resulted in mean changes from baseline in systolic/diastolic blood pressure of -5.3/-3.7 mmHg at 1 hour after dosing, compared to mean changes from baseline in the placebo group of 2.7/-0.4 mmHg. The reductions in systolic/diastolic blood pressure at 1 hour after dosing of STENDRA 200 mg compared to placebo were 8.0/3.3 mmHg.

Figure 1: Median Change from Baseline in Sitting Systolic Blood Pressure, Healthy Volunteers Day 4

Effects on Cardiac Electrophysiology

The effect of single 100 or 800 mg doses of STENDRA on the QT interval were evaluated in a randomized, double-blind, placebo, and active (moxifloxacin) –controlled crossover study in 52 healthy male subjects aged 18 to 45 years. There were no significant effects of the 100 mg dose. The mean QTc (Fridericia QT correction) for avanafil 800 mg, relative to placebo was 9.4 milliseconds (two-sided 90% CI=7.2, 11.6). An 800 mg dose of STENDRA (4 times the highest recommended dose) was chosen because this dose yields exposures greater than those observed upon co-administration of avanafil with strong CYP3A4 inhibitors. A double-blind, randomized, placebo- and active-controlled (moxifloxacin), thorough QT/QTc trial of STENDRA (100 and 800 mg) in healthy male subjects demonstrated that STENDRA did not cause any significant changes in QTc interval or ventricular repolarization.

Effects of STENDRA on Blood Pressure When Administered with Nitrates

In a clinical pharmacology trial, a single dose of STENDRA 200 mg was shown to potentiate the hypotensive effect of nitrates. The use of STENDRA in patients taking any form of nitrates is contraindicated [see Contraindications (4.1)].

A trial was conducted to assess the degree of interaction between nitroglycerin and STENDRA, should nitroglycerin be required in an emergency situation after STENDRA was taken. This was a single-center, double-blind, randomized, 3-way crossover trial of healthy males from 30 to 60 years of age. Subjects were divided among 5 trial groups with the trial group being determined by the time interval between treatment with trial drug and glyceryl trinitrate administration. Subjects were assigned to trial groups sequentially and hemodynamic results from the previous group were reviewed for serious adverse events (SAEs) before the next group received treatment. Each subject was dosed with all 3 study drugs (STENDRA 200 mg, sildenafil citrate 100 mg, and placebo) in random order. Subjects were administered a single dose of 0.4 mg sublingual nitroglycerin (NTG) at pre-specified time points, following their dose of trial drug (0.5, 1, 4, 8 or 12 hours). Overall, 14 (15%) subjects treated with placebo and 28 (28%) subjects treated with avanafil, had clinically significant decreases in standing SBP, defined as greater than or equal to 30 mmHg decrease in SBP, after glyceryl trinitrate administration. Mean maximum decreases are shown in Table 5.

Like other PDE5 inhibitors, STENDRA administration with nitrates is contraindicated. In a patient who has taken STENDRA, where nitrate administration is deemed medically necessary in a life threatening situation, at least 12 hours should elapse after the last dose of STENDRA before nitrate administration is considered. In such circumstances, nitrates should still only be administered under close medical supervision with appropriate hemodynamic monitoring [see Contraindications (4.1)].

Effects of STENDRA on Blood Pressure When Administered with Alpha-Blockers

A single-center, randomized, double-blinded, placebo-controlled, two-period crossover trial was conducted to investigate the potential interaction of STENDRA with alpha-blocker agents in healthy male subjects which consisted of two cohorts:

Cohort A (N=24): Subjects received oral doses of doxazosin once daily in the morning at 1 mg for 1 day (Day 1), 2 mg for 2 days (Days 2 – 3), 4 mg for 4 days (Days 4 – 7), and 8 mg for 11 days (Days 8 – 18). On Days 15 and 18, the subjects also received a single oral dose of either 200 mg STENDRA or placebo, according to the treatment randomization code. The STENDRA or placebo doses were administered 1.3 hours after the doxazosin administration on Days 15 and 18. The co-administration was designed so that doxazosin (Tmax ~2 hours) and STENDRA (Tmax ~0.7 hours) would reach their peak plasma concentrations at the same time.

Cohort B (N=24): Subjects received 0.4 mg daily oral doses of tamsulosin in the morning for 11 consecutive days (Days 1 – 11). On Days 8 and 11, the subjects also received a single oral dose of either 200 mg STENDRA or placebo, according to the treatment randomization code. The STENDRA or placebo doses were administered 3.3 hours after the tamsulosin administration on Days 8 and 11. The co-administration was designed so that tamsulosin (Tmax ~4 hours) and STENDRA (Tmax ~0.7 hours) would reach their peak plasma concentrations at the same time.

Supine and sitting BP and pulse rate measurements were recorded before and after STENDRA or placebo dosing.

A total of seven subjects in Cohort A (doxazosin) experienced potentially clinically important absolute values or changes from baseline in standing SBP or DBP. Three subjects experienced standing SBP values less than 85 mmHg. One subject experienced a decrease from baseline in standing SBP greater than 30 mmHg following STENDRA. Two subjects experienced standing DBP values less than 45 mmHg following STENDRA. Four subjects experienced decreases from baseline in standing DBP greater than 20 mmHg following STENDRA. One subject experienced such decreases following placebo. There were no severe adverse events related to hypotension reported during the trial. There were no cases of syncope.

A total of five subjects in Cohort B (tamsulosin) experienced potentially clinically important absolute values or changes from baseline in standing SBP or DBP. Two subjects experienced standing SBP values less than 85 mmHg following STENDRA. One subject experienced a decrease from baseline in standing SBP greater than 30 mmHg following STENDRA. Two subjects experienced standing DBP values less than 45 mmHg following STENDRA. Four subjects experienced decreases from baseline in standing DBP greater than 20 mmHg following STENDRA; one subject experienced such decreases following placebo. There were no severe adverse events related to hypotension reported during the trial. There were no cases of syncope.

Table 6 presents the placebo-subtracted mean maximum decreases from baseline (95% CI) in systolic blood pressure results for the 24 subjects who received STENDRA 200 mg and matching placebo.

Blood pressure effects (standing SBP) in normotensive men on stable dose doxazosin (8 mg) following administration of STENDRA 200 mg or placebo, are shown in Figure 2. Blood pressure effects (standing SBP) in normotensive men on stable dose tamsulosin (0.4 mg) following administration of STENDRA 200 mg or placebo are shown in Figure 3.

Figure 2: Mean (SD) Change From Baseline in Standing Systolic Blood Pressure Over Time Following Administration of a Single Dose 200 mg Dose of STENDRA with Doxazosin

Figure 3: Mean (SD) Change From Baseline in Standing Systolic Blood Pressure Over Time Following Administration of a Single Dose 200 mg Dose of STENDRA with Tamsulosin

Effects of STENDRA on Blood Pressure When Administered with Enalapril

A trial was conducted to assess the interaction of enalapril (20 mg daily) and STENDRA 200 mg. Single doses of 200 mg STENDRA co-administered with enalapril caused a mean maximum decrease in supine systolic/diastolic blood pressure of 1.8/3.5 mmHg (compared to placebo), accompanied by a mean maximum increase in pulse rate of 1.0 bpm.

Effects of STENDRA on Blood Pressure When Administered with Amlodipine

A trial was conducted to assess the interaction of amlodipine (5 mg daily) and STENDRA 200 mg. Single doses of 200 mg STENDRA co-administered with amlodipine caused a mean maximum decrease in supine systolic blood pressure of 1.2 mmHg (compared to placebo), accompanied by a mean maximum increase in pulse rate of 1.0 bpm; the mean maximum decrease in diastolic blood pressure was less than that observed in the placebo group. There was no effect of STENDRA on amlodipine plasma concentrations. Concomitant amlodipine was associated with 22% and 70% increases in avanafil Cmax and AUC, respectively.

Effects of STENDRA on Blood Pressure When Administered with Alcohol

Alcohol and PDE5 inhibitors, including STENDRA, are mild systemic vasodilators. The interaction of STENDRA with alcohol was evaluated in a clinical pharmacology trial. Alcohol was administered at a dose of 0.5 g/kg, which is equivalent to approximately 3 ounces of 80-proof vodka in a 70-kg male, and STENDRA was administered at a dose of 200 mg. All patients consumed the entire alcohol dose within 15 minutes of starting. Blood alcohol levels of 0.057% were confirmed. There were no reports of orthostatic hypotension or dizziness. Additional maximum supine systolic/diastolic blood pressure decreases of 3.5/4.5 mmHg and additional maximum pulse rate increase of 9.3 bpm were observed when avanafil was taken with alcohol compared to alcohol alone. Avanafil did not affect alcohol plasma concentrations.

Effects of STENDRA on Spermatogenesis

The effect of STENDRA on spermatogenesis was assessed in 181 healthy male volunteers who received STENDRA 100 mg or placebo daily for 26 weeks. The results of this randomized, double-blind, placebo-controlled study in 137 subjects who completed the study through Week 26 and provided 2 semen samples at baseline and at Week 26 showed no adverse effects of STENDRA on sperm concentration, total sperm count, sperm motility, sperm normal morphology, and semen volume.

Effects of STENDRA on Vision

Single oral doses of Type 5 phosphodiesterase inhibitors have demonstrated transient dose-related impairment of color discrimination (blue/green), using the Farnsworth-Munsell 100-hue test, with peak effects near the time of peak plasma levels. This finding is consistent with the inhibition of PDE6, which is involved in phototransduction in the retina.