It is therefore recommended not to exceed a maximum single dose of 25 mg of Viagra in a 48 hour period [Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil CIn a drug-drug interaction study sildenafil 50 mg given with alcohol 0.5 g/kg in which mean maximum blood alcohol levels of 0.08% was achieved, sildenafil did not potentiate the hypotensive effect of alcohol in healthy volunteers [There are no data with the use of Viagra in pregnant women to inform any drug-associated risks for adverse developmental outcomes. For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity.

To check this theory, the researchers tested the effect of Viagra on platelets. A third clotting issue is endothelial dysfunction, when the cells lining … Following a review of the data from these first 4 subjects (details provided below), the Viagra dose was reduced to 25 mg. Such an event may be a sign of non-arteritic anterior ischemic optic neuropathy (NAION), a rare condition and a cause of decreased vision including permanent loss of vision, that has been reported rarely post-marketing in temporal association with the use of all PDE5 inhibitors. 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. Viagra demonstrated statistically significant improvement compared to placebo in all 21 studies. Given sildenafil peak plasma concentrations of approximately 1 µM after recommended doses, it is unlikely that Viagra will alter the clearance of substrates of these isoenzymes.No significant interactions were shown with tolbutamide (250 mg) or warfarin (40 mg), both of which are metabolized by CYP2C9.In a study of healthy male volunteers, sildenafil (100 mg) did not affect the steady state pharmacokinetics of the HIV protease inhibitors, saquinavir and ritonavir, both of which are CYP3A4 substrates.Viagra (50 mg) did not potentiate the increase in bleeding time caused by aspirin (150 mg).Sildenafil at steady state, at a dose not approved for the treatment of erectile dysfunction (80 mg t.i.d.) There is no information on the effects on the breastfed child, or the effects on milk production.Viagra is not indicated for use in pediatric patients. It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors [Physicians should warn patients that prolonged erections greater than 4 hours and priapism (painful erections greater than 6 hours in duration) have been reported infrequently since market approval of Viagra. In addition, patients were asked a global efficacy question and an optional partner questionnaire was administered.The effect on one of the major end points, maintenance of erections after penetration, is shown in Figure 6, for the pooled results of 5 fixed-dose, dose-response studies of greater than one month duration, showing response according to baseline function. All rights reserved. The following drugs, medications, substances or toxins are some of the possible causes of Blood clots as a symptom. Such an event may be a sign of non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including possible permanent loss of vision, that has been reported rarely post-marketing in temporal association with the use of all PDE5 inhibitors. On a global improvement question, 57% of Viagra patients reported improved erections versus 10% on placebo.

Here is why that happens.

Diary data indicated that on Viagra, 48% of intercourse attempts were successful versus 12% on placebo.One randomized, double-blind, placebo-controlled, crossover, flexible-dose (up to 100 mg) study of patients with erectile dysfunction resulting from spinal cord injury (n=178) was conducted. Following at least 14 consecutive daily doses of doxazosin, Viagra 100 mg or matching placebo was administered simultaneously with doxazosin.