Which medications in the drug class Antibiotics are used in the treatment of Chronic Gastritis?

Updated: Jun 07, 2019
  • Author: Akiva J Marcus, MD, PhD; Chief Editor: BS Anand, MD  more...
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The antibiotics selected have antimicrobial activity against most H pylori strains. Rare resistant strains have been reported.

Amoxicillin (Moxatag)

Amoxicillin is an acid-stable semisynthetic penicillin. Its antimicrobial activity is pH-dependent, with the minimal inhibitory concentration (MIC) decreasing as the pH increases.

Clarithromycin (Biaxin)

Clarithromycin is a macrolide that binds to bacterial ribosomes and disrupts protein synthesis, leading to bacterial cell death. It is the most acid-stable of the macrolides and has the lowest MIC. Its major metabolite also is active against H pylori.


Tetracycline treats infections with gram-positive and gram-negative organisms, as well as mycoplasmal, chlamydial, and rickettsial infections. It inhibits bacterial protein synthesis by binding with 30S and possibly 50S ribosomal subunit(s). Its potency is affected in solutions whose pH is less than 2, and it is rapidly destroyed by alkali hydroxide solutions.

Metronidazole (Flagyl)

Metronidazole is an imidazole ring-based antibiotic that is active against various anaerobic bacteria and protozoa. It is used in combination with other antimicrobial agents. Because the activity of metronidazole is pH-independent, it is theoretically an ideal drug for the gastric environment.

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