Metronidazole Induced Aphthous Ulcer with Angular Cheilitis

Metronidazole, chemically a nitroimidazole is an antiprotozoal drug, which has broad spectrum cidal activity against anaerobic protozoa, anaerobic and microaerophillic bacteria. It was introduced in 1959 for trichomoniasis, and later found to be highly active amoebicide. Metronidazole after entering the cell by diffusion, its nitro group is reduced by certain redox proteins to a highly reactive nitro radical, which acts as an electron sink competes with the biological electron acceptors generated by cell mitochondria and hence interferes with energy metabolism. The drug is completely absorbed orally, metabolized in liver followed by renal excretion. The recommended dose is 500 to 750 mg P.O TID for 7 to 10 days. It can be given intravenously, by loading dose of 15 mg/kg is followed 6 hours later by a maintenance dose of 7.5 mg/kg every 6 hours, usually for 7 to 10 days .The common adverse effects are anorexia, nausea, metallic taste, dryness of mouth, abdominal cramps, headache, glossitis, urticaria, rashes and chronic use leads to peripheral neuropathy and CNS side effects. Here we report a case of 55 year old male suffered from metronidazole induced aphthous ulcer with angular cheilitis.