Metronidazole is indicated in the treatment of following diseases:

• The prevention of post-operative infections due to anaerobic bacteria (particularly species of bacteroides and anaerobic streptococci).
• The treatment of septicaemia, bacteraemia, peritonitis, brain abscess, pelvic abscess, pelvic cellulitis and post-operative wound infections caused by anaerobes.
• In the treatment of urogenital trichomoniasis.
• Bacterial vaginosis (also known as non-specific vaginitis).
• All forms of amoebiasis (intestinal, extra-intestinal disease and that of symptomless cyst passers).
• Giardiasis.
• Acute ulcerative gingivitis.
• Anaerobically infected leg ulcers and pressure sores.
• Acute dental infections due to anaerobic organisms.
• Antibiotic associated pseudomembranus colitis.

Amoebicides, Anti-diarrhoeal Antiprotozoal

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.

Tablet and Suspension:

Trichomoniasis (Adults & Children over 10 yrs)-

• 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

Trichomoniasis (Children)-

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

Intestinal amoebiasis (Adults & Children over 10 yrs)-

• 800 mg tid for 5 days

Intestinal amoebiasis (Children)-

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

Extra-intestinal & Asymptomatic amoebiasis (Adults & Children over 10 yrs)-

• 400-800 mg tid for 5-10 days

Extra-intestinal & Asymptomatic amoebiasis (Children)-

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

Giardiasis (Adults & Children over 10 yrs)-

• 2 gm once daily for 3 days

Giardiasis (Children)-

• 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

Acute ulcerative  gingivitis (Adults & Children over 10 yrs)-

• 200 mg tid for 3 days

Acute ulcerative  gingivitis (Children)-

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

Acute dental infections (Adults & Children over 10 yrs)-

• 200 mg tid for 3-7 days

Bacterial Vaginosis (Adults & Children over 10 yrs)-

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

Leg ulcers and pressure sores (Adults & Children over 10 yrs)-

• 400 mg tid for 7 days

Anaerobic infections (Adults & Children over 10 yrs)-

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

Anaerobic infections (Children)-

• Children 1-10 yrs: 7.5 mg/kg tid

Surgical prophylaxis (Adults & Children over 10 yrs)-

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

Surgical prophylaxis (Children)-

• Children 1-10 yrs: 7.5 mg/kg tid

Vaginal Gel:

The recommended dose is one applicator full of Metronidazole gel (approximately 5 grams containing approximately 37.5 mg of Metronidazole) intravaginally once or twice a day for 5 days. For once a day dosing, Metronidazole gel should be administered at bedtime.

Suppository:

Anaerobic Infections-

• 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.

Surgical Prophylaxis-

• 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:

Metronidazole intravenous infusion requires no dilution and should not be mixed with any other drugs prior to administration.

• 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.

Metronidazole has been found to interact with alcohol, warfarin, phenytoin, phenobarbitone, fluorouracil, disulfiram, lithium and cimetidine.

Metronidazole is contraindicated in patients with a history of hypersensitivity to Metronidazole or other Nitroimidazole derivatives.

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.

Metronidazole should be given with caution in anaemia or other blood disorders, liver disease, disease of the nervous system, seizures etc.

Keep in a dry place away from light and heat. Keep out of the reach of children.