Generic Viagra (sildenafil) is an alternative to the branded Viagra drug that can be used for treating erectile dysfunction (ED). It’s now sold by many manufacturers, including online.This finding is consistent with the inhibition of PDE6, which is involved in phototransduction in the retina. If you are taking sildenafil to treat PAH, you will probably take sildenafil three times a day with or without food. Take sildenafil exactly as directed. Based upon measurements of sildenafil in semen of healthy volunteers 90 minutes after dosing, less than 0. Flibanserin is not approved in Australia. Talk with your healthcare provider about which might be best for you. If you have an erection that lasts more than 4 hours, get medical help right away.Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is mg. Don’t take sildenafil (Viagra) more than once daily (at any dose). Written by Brian Leonard, PharmD, BCACP, BCGP. Viagra (sildenafil) is a brand-name prescription drug that’s used to treat erectile dysfunction (ED). Learn about side effects, warnings, dosage, and more. Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is .Cialis can be taken daily, providing constant treatment for ED for people who have sex frequently. Pharmacokinetic data from patients in clinical trials showed no effect on sildenafil pharmacokinetics of CYP2C9 inhibitors such as tolbutamide, warfarin , CYP2D6 inhibitors such as selective serotonin reuptake inhibitors, tricyclic antidepressants , thiazide and related diuretics, ACE inhibitors, and calcium channel blockers. If you are taking sildenafil for erectile dysfunction, your doctor will probably start you on an average dose of sildenafil and increase or decrease your dose depending on your response to the medication. The combination can cause a dangerous fall in your blood pressure. This increased blood flow can cause an erection. Efficacy Results from Controlled Clinical Studies 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.