FDA approves impotence pill.
D017277:Drug Approval; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D008297:Male; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines; D000068677:Sildenafil Citrate; D013450:Sulfones
D004791:Enzyme Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate