Using alcohol or tobacco with certain medicines may also cause interactions to occur. Erectile dysfunction for sildenafil By mouth Adult Initially 50 mg, to be taken approximately 1 hour before sexual activity, adjusted according to response to 25— mg max. No dose adjustment is required for mild to moderate hepatic impairment. It is in the phosphodiesterase-5 inhibitor PDE5-I class of medications. The result of smooth muscle cell target protein phosphorylation is a decrease in intracellular calcium, increased efflux of potassium, and deactivation of myosin light chain kinase, ultimately causing smooth muscle relaxation.AdBrowse & discover thousands of brands. Read customer reviews & find best sellers. Find deals and low prices on sildenafil mg at test1.ru1M+ visitors in the past month. The usual dose is 50mg, when you need it. Do not take it more than once a day. The dose can be increased to mg or decreased to 25mg depending on its effect. Take sildenafil up to 4 hours before you want to have sex. For sildenafil to work properly, you’ll need to be sexually excited. Sildenafil is a medication used in the management and treatment of erectile dysfunction and pulmonary arterial hypertension. It is in the phosphodiesterase-5 inhibitor (PDE5-I) class of medications. This activity describes the indications, actions, adverse effects, and contraindications of sildenafil as an agent in the clinical setting. Knowledge .