· Drug information provided by: Merative, Micromedex ® Use sildenafil exactly as directed by your doctor. Do not use more of it and do not use it more often than your doctor ordered. If too much is used, the chance of side effects is increased. This medicine comes with a patient information leaflet.Taking Viagra Sildenafil once a day is a popular choice, as it allows for more spontaneity between you and your partner. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive. This sort of problem can sometimes be resolved by moving to the lower dose. Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day. Vardenafil usually works for 4 to 5 hours. Also, men should not use the drug if they have experienced a stroke, life-threatening arrhythmia, or myocardial infarction within the last six months.Oral medicines for ED usually work well and cause few side effects. The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors.  · Drug information provided by: Merative, Micromedex ® Use sildenafil exactly as directed by your doctor. Do not use more of it and do not use it more often than your doctor ordered. If too much is used, the chance of side effects is increased. This medicine comes with a patient information leaflet. Aging Aging Finding The Right Viagra Dose For A Year-Old Male: Dosage Info January 13, Erectile dysfunction (E.D.) happens to men of all ages, but risk is closely related to age. The older you get, the .The starting sildenafil dose was 50 mg, taken 1 hour before sexual activity, with subsequent adjustment to or 25 mg based on efficacy and safety. Possible side effects of Sildenafil include nausea, dizziness, headache, a blocked nose, and facial flushing. Sildenafil should not be used with any other medicine or device that causes erections. And remember, there may be a delayed onset after a high-fat meal. It increases your libido, and helps you get and maintain an erection for longer. What Does Sildenafil Do?