Metronidazole Extended Release

Metronidazole Extended-release tablets are used for the treatment of amoebiasis, urogenital trichomoniasis & giardiasis.

Metronidazole Extended-release tablets are composed of metronidazole. Metronidazole has antiprotozoal and antibacterial actions and is effective against Trichomonas vaginalis and other protozoa including Entamoeba histolytica and Giardia lamblia and against anaerobic bacteria. Metronidazole is rapidly and almost completely absorbed on the administration of Metronidazole tablets; peak plasma concentrations occur after 20 min to 3 hours

Indications

• Metronidazole tablets are indicated for the treatment of amoebiasis, urogenital trichomoniasis & giardiasis.

Dosage and method of administration

Oral route of administration.

Metronidazole tablets should be swallowed with water (not chewed). It is recommended that the tablets be taken during or after a meal.

Amoebiasis:

Adults and children over 10 years: 600 mg four times daily for 5 days or 600 mg two times daily for 5-10 days or as directed by the physician.

Children below 10 years: As directed by the physician.

Urogenital trichomoniasis:

Adults and children over 10 years: 600 mg daily for 7 days or as directed by the physician.

Children below 10 years: As directed by the physician

Giardiasis:

Adults and children over 10 years: 600 mg two times daily for 5 days or as directed by the physician.

Children below 10 years: As directed by the physician.

Contraindications

Known hypersensitivity to nitroimidazole, metronidazole, or any of the excipients

Warnings and Precautions

• Regular clinical and laboratory monitoring (especially leucocyte count) is advised if administration of Metronidazole tablets for more than 10 days is considered to be necessary and patients should be monitored for adverse reactions, such as peripheral or central neuropathy (such as paraesthesia, ataxia, dizziness, convulsive seizures).

• Metronidazole should be used with caution in patients with active or chronic severe peripheral and central nervous system disease due to the risk of neurological aggravation.

• Cases of severe hepatotoxicity/acute hepatic failure, including cases with a fatal outcome with very rapid onset after treatment initiation in patients with Cockayne syndrome, have been reported with products containing metronidazole for systemic use. In this population, metronidazole should, therefore, be used after careful benefit-risk assessment and only if no alternative treatment is available. Liver function tests must be performed just before the start of therapy, throughout and after the end of treatment until liver function is within normal ranges, or until the baseline values are reached. If the liver function tests become markedly elevated during treatment, the drug should be discontinued.

• Patients with Cockayne syndrome should be advised to immediately report any symptoms of potential liver injury to their physician and stop taking metronidazole

• There is a possibility that after Trichomonas vaginalis has been eliminated a gonococcal infection might persist.

• 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).

• 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 the urine.

• Due to inadequate evidence on the mutagenicity risk in humans, the use of Metronidazole for longer treatment than usually required should be carefully considered.

Drug Interactions

• Patients should be advised not to take alcohol during metronidazole therapy and for at least 48 hours afterwards because of the possibility of a disulfiram-like (Antabuse effect) reaction. Psychotic reactions have been reported in patients who were using metronidazole and disulfiram concurrently.

• Some potentiation of anticoagulant therapy has been reported when metronidazole has been used with the warfarin type oral anticoagulants. Dosage of the latter may require reducing. Prothrombin times should be monitored. There is no interaction with heparin.

• Lithium retention accompanied by evidence of possible renal damage has been reported in patients treated simultaneously with lithium and metronidazole. Lithium treatment should be tapered or withdrawn before administering metronidazole. Plasma concentrations of lithium, creatinine and electrolytes should be monitored in patients under treatment with lithium while they receive metronidazole.

• Patients receiving phenobarbital or phenytoin metabolize metronidazole at a much greater rate than normal, reducing the half-life to approximately 3 hours.

• Metronidazole reduces the clearance of 5 fluorouracil and can, therefore, result in increased toxicity of 5 fluorouracil.

• Patients receiving ciclosporin are at risk of elevated ciclosporin serum levels. Serum ciclosporin and serum creatinine should be closely monitored when coadministration is necessary.

• Plasma levels of busulfan may be increased by metronidazole which may lead to severe busulfan toxicity.