Epub Aug Your doctor or other health care professional can recommend one for you based on these factors, other health conditions you have and any other medicines you take. Oral medicines for ED usually work well and cause few side effects. Millions of men worldwide suffer from erectile dysfunction ED , which is commonly treated with the popular drug Viagra. If you do, you may save money with online pharmacies that accept yours. Recent heart or blood vessel problems. · It is not recommended to take Viagra without a prescription as it can cause harmful side effects and potentially hazardous interactions, especially when mixed with . Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body .  · Drugs including Viagra and Cialis lead to an average improvement of 4 to 8 points on the scale used by researchers and clinicians. The team behind the new study .