At a lower dose, sildenafil is approved to treat pulmonary arterial hypertension—the higher dose is reserved for treating erectile dysfunction (ED). Anawalt explains that there's a chance your insurance might not cover it to treat ED. Still, if your doctor says it's okay for you to use and you end up paying out-of-pocket, you can still get the generic for a lot less than Viagra.
Nitric Oxide (NO) is released with sexual stimulation from nerve endings and endothelial cells in the corpus cavernosum of the penis. An enzyme then converts guanosine triphosphate (GTP) into cyclic guanosine monophosphate (cGMP). cGMP causes the smooth muscle of the penis to relax, which causes an inflow of blood which then leads to an erection. cGMP is then hydrolysed back to the inactive GMP by phosphodiesteras type 5 (PDE5).
A full 100 mg. will give you a Ginsu carving knife that, if put to ultimate use, will render her suitable for burial in a Y-shaped coffin. For most of us, 50 mg. is plenty, ensuring that you can return to a deflated state between orgasms, if so desired...But you may have to picture your grandmother naked, to do so.
Some medicines can cause unwanted or dangerous effects when used with Viagra. Tell your doctor about all your current medicines, especially riociguat (Adempas).