Generic versions of sildenafil, vardenafil and tadalafil are available. It depends on the platform and insurance provider. Before starting, stopping, or changing any medications while taking sildenafil, please get the advice of your doctor or pharmacist. Payment options: Consider how you’d like to pay. Follow-up support: Make sure you can get the help you need if questions or concerns arise after ordering. Other conditions that may disqualify you from an ED prescription include a history of stroke, kidney or liver disease, cancer, diabetes, or a bleeding disorder.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. This means that 4 hours after you take a dose, your body has cleared half of the dose. In most cases, it takes about 5 half-lives for your body to completely remove a drug from your system. So. 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 .