As with any narcotic, there are some unintended effects you should expect when using this device. Some regular side effects are headache, nausea, diarrhea, feeling giddy, upset abdomen, and drowsiness. The primary actions of sildenafil on the body is to improve blood flow to the male member. In conjunction with sexual activity, sildenafil shows by maximizing blood flow in the penile locale to aid men obtain and gaze after an erection. In addition , this drug would not protect against STDs (including HIV, gonorrhea, syphilis, and herpes herpes). Which is why it is important for men who want to take sildenafil to utilize a condom during sex.