Viagra 50 mg is the recommended dosage for the treatment of erectile dysfunction in men. It contains Sildenafil which helps to increase the blood flow to the penis and relax muscles. It helps achieve and sustain a firm erection during sexual activity. You can take this pill with your doctor's prescription and must take this pill approximately 30 minutes to 1 hour before sexual intercourse for effective results. The effects of this medicine can last for around 4 to 5 hours.