title: Six years of H2-antagonists.
mesh_terms: D002927:Cimetidine / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D004381:Duodenal Ulcer / Q000188:drug therapy*; D006146:Guanidines / Q000627:therapeutic use*; D006635:Histamine H2 Antagonists / Q000266:history / Q000627:therapeutic use*; D049673:History, 20th Century; D006801:Humans; D014481:United States
chemical_list: D006146:Guanidines; D006635:Histamine H2 Antagonists; D002927:Cimetidine