3-[[[2-[(Diaminomethylene)amino]thiazol-4-yl]methyl]thio]propanimidamide Dihydrochloride|Famotidine USP RC A ; 3-[[[2-[(Diaminomethylene)amino]thiazol-4-yl]methyl]sulphanyl]propanimidamide dihydrochloride.