Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day. This includes prescription or nonprescription over-the-counter [OTC] medicines and herbal or vitamin supplements. This medicine works best when you take it on an empty stomach an hour before sex. Remove the cap by pushing it down and twisting it counter-clockwise. An inherited eye disease that affects the retina. These medicines are called PDE5 inhibitors.VIAGRA can be taken with or without food. If you take VIAGRA after a high fat meal (such as a cheeseburger and french fries), VIAGRA may take a little longer to start working • Do not take VIAGRA more than 1 time a day. • If you accidentally take too much VIAGRA, call your doctor or go to the nearest hospital emergency room right away.  · VIAGRA can be taken with or without food. If you take VIAGRA after a high fat meal (such as a cheeseburger and french fries), VIAGRA may take a little longer to start working; Do not take VIAGRA more than 1 time a day. If you accidentally take too much VIAGRA, call your doctor or go to the nearest hospital emergency room right away. You need a prescription from a doctor to obtain sildenafil. You can buy it from a store-based pharmacy or reputable online pharmacy with a prescription. Some people buy sildenafil online without a prescription. This isn’t a good idea, as you can’t be sure whether these pills contain the medicine or are counterfeit. Counterfeit medicines can.