This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-Ulcer, Subject name: Pharmacology
Drug not used in the treatment of H.pylori is? 
Select and explain. 
A. Cisapride, B. Clarithromycin, C. Metronidazole, D. Omeprazole
A: Cisapride
Answer: A: Cisapride 
Explanation: ANSWER: (A) CisaprideREF: Harrison 17th ed table 144-2Recommended Treatment Regimens for Helicobacter pylori:First-Line Treatment:Regimen 1: OCA (7-14 days)Omeprazoleb (20 mg bid)Clarithromycin (500 mg bidAmoxicillin (1 g bid)Regimen 2: OCM (7-14 days)Omeprazoleb (20 mg bid)Clarithromycin (500 mg bid)Metronidazole (500 mg bid)Second-Line Treatment:Regimen 3: OBTM (14 days)Omeprazoleb (20 mg bid)Bismuth subsalicylate (2 tabs qid)Tetracycline HC1 (500 mg qid)Metronidazole (500 mg tid)