Tablet and Suspension:

• 200 mg tid or 400 mg bid for 7 days
• 800 mg in the morning and 1-2 gm at night for 2 days
• 2 gm as a single dose for 1 days

• Children 7-10 yrs: 100 mg tid
• Children 3-7 yrs: 100 mg bid
• Children 1-3 yrs: 50 mg tid

• 800 mg tid for 5 days

• Children 7-10 yrs: 400 mg tid
• Children 3-7 yrs: 200 mg qid
• Children 1-3 yrs: 200 mg tid

• 400-800 mg tid for 5-10 days

• Children 7-10 yrs: 200-400 mg tid
• Children 3-7 yrs: 100-200 mg qid
• Children 1-3 yrs: 100-200 mg tid

• 2 gm once daily for 3 days

• Children 7-10 yrs: 1 gm once daily
• Children 3-7 yrs: 600-800 mg once daily
• Children 1-3 yrs: 500 mg once daily

• 200 mg tid for 3 days

• Children 7-10 yrs: 100 mg tid
• Children 3-7 yrs: 100 mg bid
• Children 1-3 yrs: 50 mg tid

• 200 mg tid for 3-7 days

• 400 mg bid for 7 days
• 2 gm as a single dose for 1 days

• 400 mg tid for 7 days

• 800 mg initially and then 400 mg tid for 7 days

• Children 1-10 yrs: 7.5 mg/kg tid

• 400 mg tid started 24  hours before  surgery for 1 days

• Children 1-10 yrs: 7.5 mg/kg tid

Vaginal Gel:

Suppository:

• Adults: 1 g every 8 hours for 3 days, then 1 g every 12 hours.
• Children: 5-10 years: 500 mg every 8 hours for 3 days, then every 12 hours, Over 10 years adult dose.

• Adults: 1 g 2 hours before surgery; up to 3 further doses of 1 g may be given every 8 hours for high risk procedures.
• Children: 5-10 years: 500 mg 2 hours before surgery; up to 3 further doses of 500 mg may be given every 8 hours for high risk procedures.

IV Infusion:

• Adults and children over 12 years: Infuse 500 mg 8 hourly at a rate of 5 ml/minute and a maximum of 4 g should not be exceeded during a 24-hour period. Treatment for 7 days is sufficient for most patients, but treatment can be extended, especially for cases where reinfection is likely. For surgical prophylaxis, administration shortly before surgery should be followed by 8-hourly doses for the next 24 hours.
• Children under 12 years: 7.5 mg/kg body weight/day every 8 hours at a rate of 5 ml/minute.

• 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.

• 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.