For oral administration.

Metronidazole & Diloxanide Furoate tablets should be swallowed, without chewing, with half a glassful of water during or after meals.

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

Metronidazole can cause potentiation of anti-coagulant therapy when 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 Lithium treatment should be tapered or withdrawn before administering Metronidazole.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 metabolise metronidazole at a much greater rate than normally, 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.

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. 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 if no alternative treatment is available. Liver function tests must be performed just prior to the start of the therapy, throughout and after 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. Cases of severe bullous skin reaction such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) or acute generalized exanthematous pustulosis (AGEP) have been reported with metronidazole. If symptoms or signs of SJS, TEN or AGEP are present, Metronidazole treatment must be immediately 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. 

Patients should be warned that metronidazole may darken 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.