Coming together.
D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D007093:Imidazoles / Q000627:therapeutic use; D008297:Male; D010410:Penile Erection / Q000187:drug effects; D010879:Piperazines / Q000627:therapeutic use; D011687:Purines; D000068677:Sildenafil Citrate; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D014665:Vasodilator Agents / Q000627:therapeutic use
D007093:Imidazoles; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014227:Triazines; D014665:Vasodilator Agents; D000069058:Vardenafil Dihydrochloride; D000068677:Sildenafil Citrate