Table Some Clinical Uses of Metronidazole Indication Comments Infections due to obligate anaerobes (eg, intra-abdominal, pelvic, soft-tissue, periodontal, and odontogenic infections; lung abscess) Often used with other antimicrobials Bacterial vaginosis Drug of choice Crohn disease — Central nervous system infections (meningitis, brain abscess) — Endocarditis — Septicemia — Prophylaxis before intestinal surgery — Clostridioides (formerly Clostridium) difficile-induced diarrhea (pseudomembranous colitis) No longer recommended as a first-line drug Should be considered only for mild cases when vancomycin or fidaxomicin are unavailable or for severe systemic cases given in combination with vancomycin Peptic ulcers due to Helicobacter pylori For treatment and prevention of relapses Used with other drugs Acne rosacea Topical or oral use Contraindications to Metronidazole and Tinidazole Metronidazole and tinidazole are contraindicated in patients who have had an allergic reaction to it.