Tell your doctor if any of these symptoms are severe or do not go away: headache. Sildenafil is in a class of medications called phosphodiesterase PDE inhibitors. You can take sildenafil with or without food. Is my erectile dysfunction most likely temporary or chronic? Follow the manufacturer’s directions to use and clean the oral syringe. Do not take more or less of it or take it more often than prescribed by your doctor.AdRead Customer Reviews & Find Best Sellers. Free, Easy Returns On Millions Of Items. Get Deals and Low Prices On sildenafil mg On has been visited by 1M+ users in the past month. You might need to work with your doctor to find the right medication and dosage for you. Before taking any medication for erectile dysfunction, including over-the . Take sildenafil as needed before sexual activity. The best time to take sildenafil is about 1 hour before sexual activity, but you can take the medication any time from 4 hours to .