14 CLINICAL STUDIES

For these four subjects, the placebo-subtracted mean maximum decreases from baseline in supine and standing systolic blood pressures were 14.8 mmHg and 21.5 mmHg, respectively.

Two of these subjects had a standing SBP < 85mmHg.

5.6 Combination with other PDE-5 Inhibitors

For these four subjects, the placebo-subtracted mean maximum decreases from baseline in supine and standing systolic blood pressures were 14.8 mmHg and 21.5 mmHg, respectively. Two of these subjects had a standing SBP < 85mmHg. Both of these subjects were protocol violators, one due to a low baseline standing SBP, and the other due to baseline orthostatic hypotension.Study 2: Sildenafil citrate with DoxazosinIn the second study, a single oral dose of sildenafil citrate 50 mg or matching placebo was administered in a 2-period crossover design to 20 generally healthy males with BPH. Following at least 14 consecutive days of doxazosin, sildenafil citrate 50 mg or matching placebo was administered simultaneously with doxazosin 4 mg (17 subjects) or with doxazosin 8 mg (3 subjects). The mean subject age in this study was 63.9 years.Twenty subjects received sildenafil citrate 50 mg, but only 19 subjects received matching placebo.

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One patient discontinued the study prematurely due to an adverse event of hypotension following dosing with sildenafil citrate 50 mg. This patient had been taking minoxidil, a potent vasodilator, during the study.For the 19 subjects who received both sildenafil citrate and matching placebo, the placebo-subtracted mean maximum decreases from baseline (95% CI) in systolic blood pressure were as follows:The mean profiles of the change from baseline in standing systolic blood pressure in subjects treated with doxazosin in combination with 50 mg sildenafil citrate or matching placebo are shown in Figure 3.Figure 3: Mean Standing Systolic Blood Pressure Change from BaselineBlood pressure was measured after administration of sildenafil citrate at the same times as those specified for the first doxazosin study. There were two subjects who had a standing SBP of < 85 mmHg. In these two subjects, hypotension was reported as a moderately severe adverse event, beginning at approximately 1 hour after administration of sildenafil citrate 50 mg and resolving after approximately 7.5 hours. There was one subject with a decrease from baseline in standing systolic BP >30mmHg following sildenafil citrate 50 mg and one subject with a decrease from baseline in standing systolic BP > 30 mmHg following both sildenafil citrate 50 mg and placebo. Both of these subjects were protocol violators, one due to a low baseline standing SBP, and the other due to baseline orthostatic hypotension.Study 2: Sildenafil citrate with DoxazosinIn the second study, a single oral dose of sildenafil citrate 50 mg or matching placebo was administered in a 2-period crossover design to 20 generally healthy males with BPH. Following at least 14 consecutive days of doxazosin, sildenafil citrate 50 mg or matching placebo was administered simultaneously with doxazosin 4 mg (17 subjects) or with doxazosin 8 mg (3 subjects). The mean subject age in this study was 63.9 years.Twenty subjects received sildenafil citrate 50 mg, but only 19 subjects received matching placebo. One patient discontinued the study prematurely due to an adverse event of hypotension following dosing with sildenafil citrate 50 mg. This patient had been taking minoxidil, a potent vasodilator, during the study.For the 19 subjects who received both sildenafil citrate and matching placebo, the placebo-subtracted mean maximum decreases from baseline (95% CI) in systolic blood pressure were as follows:The mean profiles of the change from baseline in standing systolic blood pressure in subjects treated with doxazosin in combination with 50 mg sildenafil citrate or matching placebo are shown in Figure 3.Figure 3: Mean Standing Systolic Blood Pressure Change from BaselineBlood pressure was measured after administration of sildenafil citrate at the same times as those specified for the first doxazosin study. There were two subjects who had a standing SBP of < 85 mmHg. In these two subjects, hypotension was reported as a moderately severe adverse event, beginning at approximately 1 hour after administration of sildenafil citrate 50 mg and resolving after approximately 7.5 hours. There was one subject with a decrease from baseline in standing systolic BP >30mmHg following sildenafil citrate 50 mg and one subject with a decrease from baseline in standing systolic BP > 30 mmHg following both sildenafil citrate 50 mg and placebo. There were no severe adverse events potentially related to blood pressure and no episodes of syncope reported in this study.Study 3: Sildenafil citrate with DoxazosinIn the third study, a single oral dose of sildenafil citrate 100 mg or matching placebo was administered in a 3-period crossover design to 20 generally healthy males with BPH. In dose period liquid sildenafil citrate 1, subjects were administered open-label doxazosin and a single dose of sildenafil citrate 50 mg simultaneously, after at least 14 consecutive days of doxazosin. If a subject did not successfully complete this first dosing period, he was discontinued from the study. Subjects who had successfully completed the previous doxazosin interaction study (using sildenafil citrate 50 mg), including no significant hemodynamic adverse events, were allowed to skip dose period 1. Treatment with doxazosin continued for at least 7 days after dose period 1. Thereafter, sildenafil citrate 100 mg or matching placebo was administered simultaneously with doxazosin 4 mg (14 subjects) or doxazosin 8 mg (6 subjects) in standard crossover fashion.

The mean subject age in this study was 66.4 years.Twenty-five subjects were screened.

2.3 Dosage Adjustments in Specific Situations

Two were discontinued after study period 1: one failed to meet pre-dose screening qualifications and the other experienced symptomatic hypotension as a moderately severe adverse event 30 minutes after dosing with open-label sildenafil citrate 50 mg. Of the twenty subjects who were ultimately assigned to treatment, a total of 13 subjects successfully completed dose period 1, and seven had successfully completed the previous doxazosin study (using sildenafil citrate 50 mg).For the 20 subjects who received sildenafil citrate 100 mg and matching placebo, the placebo-subtracted mean maximum decreases from baseline (95% CI) in systolic blood pressure were as follows:The mean profiles of the change from baseline in standing systolic blood pressure in subjects treated with doxazosin in combination with 100 mg sildenafil citrate or matching placebo are shown in Figure 4.Figure 4: Mean Standing Systolic Blood Pressure Change from BaselineBlood pressure was measured after administration of sildenafil citrate at the same times as those specified for the previous doxazosin studies. There were three subjects who had a standing SBP of < 85 mmHg. All three were taking sildenafil citrate 100 mg, and all three reported mild adverse events at the time of reductions in standing SBP, including vasodilation and lightheadedness. There were four subjects with a decrease from baseline in standing systolic BP > 30 mmHg following sildenafil citrate 100 mg, one subject with a decrease from baseline in standing systolic BP > 30 mmHg following placebo and one subject with a decrease from baseline in standing systolic BP > 30 mmHg following both sildenafil citrate and placebo. While there were no severe adverse events potentially related to blood pressure reported in this study, one subject reported moderate vasodilatation after both sildenafil citrate 50 mg and 100 mg. There were no episodes of syncope reported in this study.Effect of Sildenafil citrate on Blood Pressure When Co-administered with Anti-hypertensives:When sildenafil citrate 100 mg oral was co-administered with amlodipine, 5 mg or 10 mg oral, to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic.Effect of Sildenafil citrate on Blood Pressure When Co-administered with Alcohol:Sildenafil citrate (50 mg) did not potentiate the hypotensive effect of alcohol (0.5 g/kg) in healthy volunteers with mean maximum blood alcohol levels of 0.08%.

• Sildenafil use should be disclosed to your healthcare provider.
• Not suitable for men with severe cardiovascular conditions.
• Ask about possible drug interactions before starting.
• Adjustments may be needed for older adults.
• Timing of medication is important for maximum effect.
• Monitoring for side effects helps prevent complications.
• Stop using sildenafil if health issues arise.
• Always follow professional medical advice.

The maximum observed decrease in systolic blood pressure was -18.5 mmHg when sildenafil was co-administered with alcohol versus -17.4 mmHg when alcohol was administered alone.

12.3 Pharmacokinetics

Both sildenafil and the metabolite have terminal half lives of about 4 hours.Mean sildenafil plasma concentrations measured after the administration of a single oral dose of 100 mg to healthy male volunteers is depicted below:Figure 5: Mean Sildenafil Plasma Concentrations in Healthy Male Volunteers.Absorption and Distribution:Sildenafil citrate is rapidly absorbed. Maximum observed plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state. When sildenafil citrate is taken with a high fat meal, the rate of absorption is reduced, with a mean delay in T maxof 60 minutes and a mean reduction in C maxof 29%. The maximum observed decrease in diastolic blood pressure was -17.2 mmHg when sildenafil was co-administered with alcohol versus -11.1 mmHg when alcohol was administered alone. There were no reports of postural dizziness or orthostatic hypotension. The maximum recommended dose of 100 mg sildenafil was not evaluated in this study [ see Drug Interactions (7.5)].Effects of Sildenafil citrate on Cardiac Parameters:Single oral doses of sildenafil up to 100 mg produced no clinically relevant changes in the ECGs of normal male volunteers.Studies have produced relevant data on the effects of sildenafil citrate on cardiac output.

• Sildenafil tablets 125 mg are available by prescription only.
• They work by inhibiting the PDE5 enzyme.
• Do not mix sildenafil with alcohol to avoid adverse effects.
• Use with caution if you have heart or liver conditions.
• Sildenafil may interact with certain antibiotics.
• Be aware of potential side effects like flushing.
• Take sildenafil about 30-60 minutes before activity.
• Avoid using grapefruit juice while on sildenafil.

In one small, open-label, uncontrolled, pilot study, eight patients with stable ischemic heart disease underwent Swan-Ganz catheterization. A total dose of 40 mg sildenafil was administered by four intravenous infusions.The results from this pilot study are shown in Table 3; the mean resting systolic and diastolic blood pressures decreased by 7% and 10% compared to baseline in these patients.

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There were no severe adverse events potentially related to blood pressure and no episodes of syncope reported in this study.Study 3: Sildenafil citrate with DoxazosinIn the third study, a single oral dose of sildenafil citrate 100 mg or matching placebo was administered in a 3-period crossover design to 20 generally healthy males with BPH. In dose period liquid sildenafil citrate 1, subjects were administered open-label doxazosin and a single dose of sildenafil citrate 50 mg simultaneously, after at least 14 consecutive days of doxazosin. If a subject did not successfully complete this first dosing period, he was discontinued from the study. Subjects who had successfully completed the previous doxazosin interaction study (using sildenafil citrate 50 mg), including no significant hemodynamic adverse events, were allowed to skip dose period 1. Treatment with doxazosin continued for at least 7 days after dose period 1.

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Thereafter, sildenafil citrate 100 mg or matching placebo was administered simultaneously with doxazosin 4 mg (14 subjects) or doxazosin 8 mg (6 subjects) in standard crossover fashion. The mean subject age in this study was 66.4 years.Twenty-five subjects were screened. Two were discontinued after study period 1: one failed to meet pre-dose screening qualifications and the other experienced symptomatic hypotension as a moderately severe adverse event 30 minutes after dosing with open-label sildenafil citrate 50 mg. Of the twenty subjects who were ultimately assigned to treatment, a total of 13 subjects successfully completed dose period 1, and seven had successfully completed the previous doxazosin study (using sildenafil citrate 50 mg).For the 20 subjects who received sildenafil citrate 100 mg and matching placebo, the placebo-subtracted mean maximum decreases from baseline (95% CI) in systolic blood pressure were as follows:The mean profiles of the change from baseline in standing systolic blood pressure in subjects treated with doxazosin in combination with 100 mg sildenafil citrate or matching placebo are shown in Figure 4.Figure 4: Mean Standing Systolic Blood Pressure Change from BaselineBlood pressure was measured after administration of sildenafil citrate at the same times as those specified for the previous doxazosin studies. There were three subjects who had a standing SBP of < 85 mmHg. Mean resting values for right atrial pressure, pulmonary artery pressure, pulmonary artery occluded pressure and cardiac sildenafil oral jelly 100mg output decreased by 28%, 28%, 20% and 7% respectively. Even though this total dosage produced plasma sildenafil concentrations which were approximately 2 to 5 times higher than the mean maximum plasma concentrations following a single oral dose of 100 mg in healthy male volunteers, the hemodynamic response to exercise was preserved in these patients.In a double-blind study, 144 patients with erectile dysfunction and chronic stable angina limited by exercise, not receiving chronic oral nitrates, were randomized to a single dose of placebo or sildenafil citrate 100 mg 1 hour prior to exercise testing. The primary endpoint was time to limiting angina in the evaluable cohort. The mean times (adjusted for baseline) to onset of limiting angina were 423.6 and 403.7 seconds for sildenafil (N=70) and placebo, respectively. These results demonstrated that the effect of sildenafil citrate on the primary endpoint was statistically non-inferior to placebo.Effects of Sildenafil citrate on Vision:At single oral doses of 100 mg and 200 mg, transient dose-related impairment of color discrimination was detected 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.

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Mean resting values for right atrial pressure, pulmonary artery pressure, pulmonary artery occluded pressure and cardiac sildenafil oral jelly 100mg output decreased by 28%, 28%, 20% and 7% respectively. Even though this total dosage produced plasma sildenafil concentrations which were approximately 2 to 5 times higher than the mean maximum plasma concentrations following a single oral dose of 100 mg in healthy male volunteers, the hemodynamic response to exercise was preserved in these patients.In a double-blind study, 144 patients with erectile dysfunction and chronic stable angina limited by exercise, not receiving chronic oral nitrates, were randomized to a single dose of placebo or sildenafil citrate 100 mg 1 hour prior to exercise testing. The primary endpoint was time to limiting angina in the evaluable cohort. The mean times (adjusted for baseline) to onset of limiting angina were 423.6 and 403.7 seconds for sildenafil (N=70) and placebo, respectively. These results demonstrated that the effect of sildenafil citrate on the primary endpoint was statistically non-inferior to placebo.Effects of Sildenafil citrate on Vision:At single oral doses of 100 mg and 200 mg, transient dose-related impairment of color discrimination was detected using the Farnsworth-Munsell 100-hue test, with peak effects near the time of peak plasma levels.

Drugs you should not use with sildenafil

This finding is consistent with the inhibition of PDE6, which is involved in phototransduction in the retina. Subjects in the study reported this finding as difficulties in discriminating blue/green. An evaluation of visual function at doses up to twice the maximum recommended dose revealed no effects of sildenafil citrate on visual acuity, intraocular pressure, or pupillometry.Effects of Sildenafil citrate on Sperm:There was no effect on sperm motility or morphology after single 100 mg oral doses of sildenafil citrate in healthy volunteers.12.3 PharmacokineticsSildenafil citrate is rapidly absorbed after oral administration, with a mean absolute bioavailability of 41% (range 25 to 63%). The pharmacokinetics of sildenafil are dose-proportional over the recommended dose range. It is eliminated predominantly by hepatic metabolism (mainly CYP3A4) and is converted to an active metabolite with properties similar to the parent, sildenafil. Subjects in the study reported this finding as difficulties in discriminating blue/green.

17. Patient Counseling Information

All three were taking sildenafil citrate 100 mg, and all three reported mild adverse events at the time of reductions in standing SBP, including vasodilation and lightheadedness. There were four subjects with a decrease from baseline in standing systolic BP > 30 mmHg following sildenafil citrate 100 mg, one subject with a decrease from baseline in standing systolic BP > 30 mmHg following placebo and one subject with a decrease from baseline in standing systolic BP > 30 mmHg following both sildenafil citrate and placebo. While there were no severe adverse events potentially related to blood pressure reported in this study, one subject reported moderate vasodilatation after both sildenafil citrate 50 mg and 100 mg. There were no episodes of syncope reported in this study.Effect of Sildenafil citrate on Blood Pressure When Co-administered with Anti-hypertensives:When sildenafil citrate 100 mg oral was co-administered with amlodipine, 5 mg or 10 mg oral, to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic.Effect of Sildenafil citrate on Blood Pressure When Co-administered with Alcohol:Sildenafil citrate (50 mg) did not potentiate the hypotensive effect of alcohol (0.5 g/kg) in healthy volunteers with mean maximum blood alcohol levels of 0.08%. The maximum observed decrease in systolic blood pressure was -18.5 mmHg when sildenafil was co-administered with alcohol versus -17.4 mmHg when alcohol was administered alone.

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The maximum observed decrease in diastolic blood pressure was -17.2 mmHg when sildenafil was co-administered with alcohol versus -11.1 mmHg when alcohol was administered alone. There were no reports of postural dizziness or orthostatic hypotension. The maximum recommended dose of 100 mg sildenafil was not evaluated in this study [ see Drug Interactions (7.5)].Effects of Sildenafil citrate on Cardiac Parameters:Single oral doses of sildenafil up to 100 mg produced no clinically relevant changes in the ECGs of normal male volunteers.Studies have produced relevant data on the effects of sildenafil citrate on cardiac output. In one small, open-label, uncontrolled, pilot study, eight patients with stable ischemic heart disease underwent Swan-Ganz catheterization. A total dose of 40 mg sildenafil was administered by four intravenous infusions.The results from this pilot study are shown in Table 3; the mean resting systolic and diastolic blood pressures decreased by 7% and 10% compared to baseline in these patients. An evaluation of visual function at doses up to twice the maximum recommended dose revealed no effects of sildenafil citrate on visual acuity, intraocular pressure, or pupillometry.Effects of Sildenafil citrate on Sperm:There was no effect on sperm motility or morphology after single 100 mg oral doses of sildenafil citrate in healthy volunteers.12.3 PharmacokineticsSildenafil citrate is rapidly absorbed after oral administration, with a mean absolute bioavailability of 41% (range 25 to 63%). The pharmacokinetics of sildenafil are dose-proportional over the recommended dose range.

• For best results, take sildenafil on an empty stomach.
• Eating fatty foods may delay its onset.
• The medication should be taken approximately 30 minutes before activity.
• Do not double dose to compensate for missed doses.
• Keep regular medical appointments during treatment.
• Report any worsening of symptoms to your doctor.
• Never use sildenafil if experiencing chest pain without medical guidance.
• Always follow the prescribed health regimen.

It is eliminated predominantly by hepatic metabolism (mainly CYP3A4) and is converted to an active metabolite with properties similar to the parent, sildenafil. Both sildenafil and the metabolite have terminal half lives of about 4 hours.Mean sildenafil plasma concentrations measured after the administration of a single oral dose of 100 mg to healthy male volunteers is depicted below:Figure 5: Mean Sildenafil Plasma Concentrations in Healthy Male Volunteers.Absorption and Distribution:Sildenafil citrate is rapidly absorbed. Maximum observed plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state. When sildenafil citrate is taken with a high fat meal, the rate of absorption is reduced, with a mean delay in T maxof 60 minutes and a mean reduction in C maxof 29%.