The majority of men who use sildenafil have pre-existing conditions such as heart disease and diabetes and are taking some sort of long-term medications. Do not be worried as our doctors will check your suitability for sildenafil via health survey or teleconsultation to ensure your safety. For example, if you are taking nitrate-containing medications (e.g. GTN, isosorbide mononitrate), sildenafil might not be suitable for you.