Generic

Metronidazole

Indications

Metronidazole is used to treat the following conditions:

• Prevent postoperative infections caused by anaerobic bacteria (especially anaerobic Bacteroides and streptococci).
•  reatment of sepsis, bacteremia, peritonitis, brain abscess, pelvic abscess, pelvic cellulitis, and postoperative wound infection caused by anaerobic bacteria.
• Treatment of genitourinary trichomoniasis.
• Bacterial vaginitis (also called nonspecific vaginitis).
• All forms of amebiasis (transmitted by intestinal and extraintestinal diseases and asymptomatic cysts).
• Giardiasis.
• Acute ulcerative gingivitis.
• Leg ulcers and pressure sores with anaerobic infection.
• Acute tooth infection caused by anaerobic organisms.
• Antibiotic-related pseudomembranous colitis.

Pharmacology

Metronidazole is an antibacterial medication that belongs to the imidazole family and is used as an antiprotozoal agent. Anaerobes decrease the 5-nitro group of Metronidazole metabolically. Metronidazole's bactericidal effect is due to the reduced form of the antibiotic interacting with DNA, according to studies.

Dosage & Administration

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.

Interaction

• Disulfiram: Patients taking metronidazole and disulfiram at the same time are reported to have psychotic reactions.
• Alcohol: Alcoholic beverages and drugs containing alcohol should not be consumed during treatment and for at least one day after treatment, as disulfiram-like reactions (anti-abuse effect) (flushing, vomiting, tachycardia) may occur. Oral anticoagulant therapy (warfarin type): increased anticoagulant effect, decreased liver catabolism and increased risk of bleeding. In the case of co-administration, prothrombin time should be monitored more frequently and anticoagulant therapy should be adjusted during treatment with metronidazole.
• Lithium: Metronidazole can increase plasma levels of lithium.
• Cyclosporine: When co-administration is required, serum cyclosporine and serum creatinine should be closely monitored.
• Phenytoin or Phenobarbital: Increased elimination of metronidazole leads to a decrease in plasma levels.
• 5-Fluorouracil: The clearance rate of 5-Fluorouracil is reduced, leading to an increase in the toxicity of 5-Fluorouracil.
• Busulfan: Metronidazole can increase the plasma concentration of busulfan, leading to severe busulfan toxicity.

Contraindications

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

Side Effects

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

Pregnancy & Lactation

Metronidazole is classified as a pregnancy category B by the US Food and Drug Administration. However, no appropriate and well-controlled trials in pregnant women have been conducted. Because animal reproduction studies do not always anticipate human response, this medication should only be taken during pregnancy if absolutely necessary. Human milk has been found to contain metronidazole. When Metronidazole is given to a breastfeeding mother, care should be used.

Precautions & Warnings

If metronidazole must be given for a longer period of time than is typically suggested, it is recommended that hematological tests, particularly leucocyte counts, be performed on a regular basis and that patients be watched for adverse responses such as peripheral or central neuropathy (such as paresthesia, ataxia, dizziness, convulsive seizures).

Patients with hepatic encephalopathy should be given metronidazole with care.

Metronidazole might cause urine to discolor, therefore patients should be informed.

Therapeutic Class

Amoebicides, Anti-diarrhoeal Antiprotozoal

Storage Conditions

Keep it below 30°C. Protect yourself from the sun. Medicines should be kept out of the reach of youngsters. Do not use beyond the expiration date.