Viagra: beyond the jokes.
D006152:Cyclic GMP / Q000378:metabolism; D004347:Drug Interactions; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D007022:Hypotension / Q000139:chemically induced; D008297:Male; D009566:Nitrates / Q000009:adverse effects; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D011687:Purines; D012307:Risk Factors; D000068677:Sildenafil Citrate; D013450:Sulfones
D009566:Nitrates; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D006152:Cyclic GMP