Viagra Clinical Pharmacology

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Viagra - Clinical Pharmacology [Sildenafil Citrate]

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.

TABLE 1. HEMODYNAMIC DATA IN PATIENTS WITH STABLE ISCHEMIC HEART DISEASE AFTER IV ADMINISTRATION OF 40 MG SILDENAFIL
Means ą SDAt restAfter 4 minutes of exercisenBaseline (B2)nSildenafil (D1)nBaselinenSildenafilPAOP (mmHg)88.1 ą 5.186.5 ą 4.3836.0 ą 13.7827.8 ą 15.3Mean PAP (mmHg)816.7 ą 4812.1 ą 3.9839.4 ą 12.9831.7 ą 13.2Mean RAP (mmHg)75.7 ą 3.784.1 ą 3.7----Systolic SAP (mmHg)8150.4 ą 12.48140.6 ą 16.58199.5 ą 37.48187.8 ą 30.0Diastolic SAP (mmHg)873.6 ą 7.8865.9 ą 10884.6 ą 9.7879.5 ą 9.4Cardiac output (L/min)85.6 ą 0.985.2 ą 1.1811.5 ą 2.4810.2 ą 3.5Heart rate (bpm)867 ą 11.1866.9 ą 128101.9 ą 11.6899.0 ą 20.4In 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 VIAGRA 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 VIAGRA on the primary endpoint was statistically non-inferior to placebo.

Effects of VIAGRA on Vision

At single oral doses of 100 mg and 200 mg, transient dose-related impairment of color discrimination (blue/green) 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. An evaluation of visual function at doses up to twice the maximum recommended dose revealed no effects of VIAGRA on visual acuity, intraocular pressure, or pupillometry.