<prompt> Drug used for penile erection -SildenaphilApomorphinePapaverineAll of the above  <response>: Ans. isdi.e., All of the aboveRef KDT fle p. 303-304 6 e p. 296; Katzung LLthe p. 197Drugs used in erectile dysfunctionPhosphodiesterase-S inhibitors Sildenafil, Todafil, VardenafilAlprostadil Prostaglandin El 