Amogit

Metronidazole is a member of the imidazole class of antibacterial drug and is classified therapeutically as an antiprotozoal agent. The 5-nitro group of Metronidazole is reduced by anaerobes metabolically. Studies have demonstrated that the reduced form of this drug interacts with DNA and gives bactericidal action of Metronidazole.

• Disulfiram: Psychotic reactions have been reported in patients who were using metronidazole and disulfiram concurrently.
• Alcohol: Alcoholic beverages and drugs containing alcohol should not be consumed during therapy and for at least one day afterwards because of the possibility of a disulfiram-like (antabuse effect) reaction (flushing, vomiting, tachycardia). Oral anticoagulant therapy (warfarin type): Potentiation of the anticoagulant effect and increased hemorrhagic risk caused by decreased hepatic catabolism. In case of co-administration, prothrombin time should be more frequently monitored and anticoagulant therapy adjusted during treatment with metronidazole.
• Lithium: Plasma levels of lithium may be increased by metronidazole.
• Cyclosporin: Serum cyclosporin and serum creatinine should be closely monitored when co-administration is necessary.
• Phenytoin or phenobarbital: increased elimination of metronidazole resulting in reduced plasma levels.
• 5-Fluorouracil: Reduced clearance of 5-fluorouracil resulting in increased toxicity of 5-fluorouracil.
• Busulfan: Plasma levels of busulfan may be increased by metronidazole, which may lead to severe busulfan toxicity.

Metallic taste, nausea, vomiting, diarrhoea, drowsiness, rashes may be observed during treatment.

US FDA Pregnancy Category of Metronidazole is B. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Metronidazole have been shown to be excreted in human milk. So, caution should be exercised when Metronidazole is administered to a nursing woman.

• If for compelling reasons, metronidazole must be administered longer than the usually recommended duration, it is recommended that hematological tests, especially leucocyte count should be carried out regularly and that patients should be monitored for adverse reactions such as peripheral or central neuropathy (such as paresthesia, ataxia, dizziness, convulsive seizures).
• Metronidazole should be administered with caution to patients with hepatic encephalopathy.
• Patients should be warned that metronidazole may darken urine.

Hepatic impairment: Metronidazole is mainly metabolised by hepatic oxidation. Substantial impairment of metronidazole clearance may occur in the presence of advanced hepatic insufficiency. Significant cumulation may occur in patients with hepatic encephalopathy and the resulting high plasma concentrations of metronidazole may contribute to the symptoms of the encephalopathy. Metronidazole should therefore, be administered with caution to patients with hepatic encephalopathy. The daily dosage should be reduced to one third and may be administered once daily. Patients should be warned that metronidazole may darken urine.

Renal impairment: The elimination half-life of metronidazole remains unchanged in the presence of renal failure. The dosage of metronidazole therefore needs no reduction. Such patients however retain the metabolites of metronidazole. The clinical significance of this is not known at present. In patients undergoing haemodialysis metronidazole and metabolites are efficiently removed during an eight hour period of dialysis. Metronidazole should therefore be re-administered immediately after haemodialysis. No routine adjustment in the dosage of Metronidazole need be made in patients with renal failure undergoing intermittent peritoneal dialysis (IDP) or continuous ambulatory peritoneal dialysis (CAPD).

Amoebicides, Anti-diarrhoeal Antiprotozoal

Single oral doses of metronidazole, up to 12 g have been reported in suicide attempts and accidental overdoses. Symptoms were limited to vomiting, ataxia and slight disorientation. There is no specific antidote for metronidazole overdosages. In case of suspected massive overdosages, a symptomatic and supportive treatment should be instituted.

Store below 30°C. Keep protected from light. Keep medicines out of the reach of children. Do not use later than the date of expiry.