Herbal viagras, contrary to what the name suggests, do not normally contain sildenafil citrate. However, synthetic chemical compounds similar to sildenafil have been found as adulterants in many supplements which are sold as herbal viagra or "natural" sexual enhancement products. Besides treating the underlying causes such as potassium deficiency or arsenic contamination of drinking water, the first line treatment of erectile dysfunction consists of a trial of PDE5 inhibitor drugs. As well as erectile dysfunction, sildenafil citrate is also effective in the rare disease pulmonary arterial hypertension (PAH). It relaxes the arterial wall, leading to decreased pulmonary arterial resistance and pressure. Protease inhibitors inhibit the metabolism of sildenafil, effectively multiplying the plasma levels of sildenafil, increasing the incidence and severity of side effects. It is recommended that patients using protease inhibitors limit their use of sildenafil to no more than one 25 mg dose every 48 hours. Protease inhibitors inhibit the metabolism of sildenafil, effectively multiplying the plasma levels of sildenafil, increasing the incidence and severity of side effects. The drug also slows down plant ripening; tests were done strawberries, legumes, roses, carnations, broccoli, and other perishables. This class of analogs has not undergone any of the rigorous testing that drugs like sildenafil have passed, and, thus, has an unknown side-effect profile.
