Question: What is the correct code for billing cimetidine 300 mg intravenously to Medicare? Vermont Subscriber Answer: Your Medicare code will be J3490 (Unclassified drugs) x 1 and you-ll put cimetidine HCl injection 300 mg in line 19. It might seem strange that Medicare doesn't cover this drug. Marketed in pill form as Tagamet, cimetidine -- which treats heartburn and peptic ulcers -- became the first drug to reach more than $1 billion a year in sales. It's since been overtaken by stomach-acid inhibitors like ranitidine (J2780, Injection, ranitidine HCL, 25 mg), which cause reduced adverse effects. There is an S-code, S0023 (Injection, cimetidine HCl, 300 mg), for those patients who have Blue Cross Blue Shield coverage.