Paper II — 2022 October (Supplementary) (2010 Scheme) — Q7
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Paper II
2022 October (Supplementary) (2010 Scheme)
Question
Metronidazole
Q73 marksShort Notes
Answer
Metronidazole is a nitroimidazole antimicrobial with combined antibacterial and antiprotozoal activity.
MOA: metronidazole → reduced by anaerobic/microaerophilic organisms’ ferredoxin-mediated electron transport (a reduction step aerobic organisms cannot perform) → generates cytotoxic free-radical/nitroso intermediates → DNA strand breakage and cell death. This oxygen-dependent activation explains its selectivity for anaerobes and microaerophilic protozoa.
Uses: anaerobic bacterial infections, amoebiasis (tissue-invasive disease), giardiasis, trichomoniasis, H. pylori eradication (as part of quadruple/alternative triple therapy), pseudomembranous (C. difficile) colitis, surgical anaerobic prophylaxis.
Adverse effects: metallic taste, nausea, peripheral neuropathy with prolonged use, disulfiram-like reaction with alcohol (inhibits aldehyde dehydrogenase, causing flushing, vomiting, palpitations if alcohol is consumed — patients counselled to avoid alcohol during and for some days after treatment).
