<p>Viagra (sildenafil) is a drug used to treat male impotence (ED). It works by increasing blood flow to the penis, helping men achieve and maintain erections during sexual stimulation.The time required for Viagra to begin to play its role may vary according to multiple factors such as individual metabolism, age and overall health.비아그라 효능 시간 But on average,t usually takes 30-60 minutes for Viagra to start working after eating.</p>