Metronidazole

Metronidazole is an antibiotic medicine that helps your body fight infections caused by bacteria and parasites. It is used to treat infections of the liver, stomach, intestines, vagina, brain, heart, lungs, bones and skin. Metronidazole helps prevent an infection after surgery. It is also used in the treatment of dental infections, leg ulcers and pressure sores. This medicine is best taken after eating some food. It should be taken at the same time each day to get the most benefit. The amount you are advised will depend on what you are being treated for and how bad it is, but you should take this antibiotic exactly as prescribed by your doctor. Your symptoms may get better after a short time but do not stop taking it until you have finished a full course of treatment, even if you feel well. If you stop taking it early, some bacteria may survive, and the infection may come back. Do not drink any alcohol while taking this medicine and for a few days after stopping it. Otherwise, you may get unpleasant side effects like nausea, vomiting and stomach pain. The most common side effects of this medicine are headache, dryness in mouth, nausea, and a slight metallic taste in the mouth. These are usually mild but let your doctor know if they bother you or last more than a few days. You can try using sugarless candies or lozenges to overcome any dryness or metallic taste in the mouth. Before using this medicine, inform your doctor if you are allergic to any medicine or have any kidney or liver problems or any disease of the nervous system. Your doctor may change the dose or prescribe a different medicine. If you are pregnant or breastfeeding, inform your doctor before taking this medicine. Metronidazole is an antibiotic. It kills the bacteria and other microorganisms that cause infections by damaging their DNA.

Bacterial infections Parasitic infections Anaerobic bacterial infections (septicemia, peritonitis, brain abscess, pelvic abscess) Prevention of post-operative infections Amoebiasis (intestinal & extra-intestinal) Trichomoniasis Giardiasis Bacterial vaginosis Acute necrotizing ulcerative gingivitis H. pylori eradication in peptic ulcer Leg ulcers and pressure sores Acute dental infections

Amoebicides, Anti-diarrhoeal Antiprotozoal

Nitroimidazole Antibiotic

Metronidazole belongs to the imidazole class of antibacterial drugs and is classified as an antiprotozoal agent. Its 5-nitro group is reduced metabolically by anaerobes. This reduced form interacts with DNA, causing destruction of helical DNA structure and strand breakage, leading to protein synthesis inhibition and cell death.

Metronidazole is converted to reduction products that interact w/ DNA to cause destruction of helical DNA structure and strand leading to a protein synthesis inhibition and cell death in susceptible organisms. It is active against most anaerobic protozoa, some gm+ve, gm-ve and facultative anaerobes.

Adult Dose: Oral Child: PO 30–50 mg/kg/day q8h Amoebiasis Adult: 800 mg tid for 5 days (intestinal infection); 5-10 days (extra-intestinal infection). Max: 2.4 g/day. Trichomoniasis Adult: 2 g as a single dose, 200 mg tid for 7 days or 400 mg bid for 5-7 days. Sexual partners should also be treated. Repeat treatment 4-6 wk between courses as necessary. Giardiasis Adult: 2 g once daily for 3 days, 400 mg tid for 5 days or 500 mg bid for 7-10 days. Bacterial vaginosis Adult: 2 g as a single dose or 400 mg bid for 5-7 days. Acute necrotising ulcerative gingivitis Adult: 200 mg tid for 3 days. Anaerobic bacterial infections Adult: Initially, 800 mg followed by 400 mg 8 hrly. Alternatively, 7.5 mg/kg 6-8 hrly. Max: 4 g/day. Duration of treatment is usually for 7 days depending on the severity of infection. Prophylaxis of postoperative anaerobic bacterial infections Adult: 400 mg 8 hrly 24 hr prior to surgery followed by post-op IV or rectal admin until oral therapy is possible. Eradication of H. pylori associated with peptic ulcer disease Adult: 400 mg bid in combination w/ another antibacterial and a PPI or 400 mg tid, if given w/ omeprazole and amoxicillin. Initial treatment is given for 1 wk. Leg ulcers and pressure sores Adult: 400 mg tid for 7 days. Acute dental infections Adult: 200 mg tid for 3-7 days. Intravenous Children: IV 22.5–40 mg/kg/day q8h Anaerobic bacterial infections Adult: 500 mg infused as 100 mL of a 5 mg/mL soln at 5 mL/min 8 hrly. Alternatively, 15 mg/kg infused over 1 hr, followed by 7.5 mg/kg infused over 1 hr 6 hrly. Max: 4 g/day. Substitute oral therapy as soon as possible. Prophylaxis of postoperative anaerobic bacterial infections Adult: 500 mg shortly before operation and repeated 8 hrly. Alternatively, 15 mg/kg infused over 30-60 min and completed approx 1 hr before surgery, followed by 7.5 mg/kg infused over 30-60 min at 6 and 12 hr after the initial dose. Hepatic impairment: Severe: 1/3 of usual dose once daily. Child Dose: Oral Amoebiasis Child: 1-3 yr 100-200 mg tid; >3-7 yr 100-200 mg 4 times daily; >7-10 yr 200-400 mg tid. Doses are given for 5-10 days. Trichomoniasis Child: 1-10 yr 40 mg/kg as a single dose or 15-30 mg/kg daily in 2-3 divided doses for 7 days. Max: 2 g/dose. Giardiasis Child: 1-3 yr 500 mg once daily; >3-7 yr 600-800 mg once daily; >7-10 yr 1 g once daily. Doses are given for 3 days. Acute necrotising ulcerative gingivitis Child: 1-3 yr 50 mg tid; >3-7 yr 100 mg bid; >7-10 yr 100 mg tid. Doses are given for 3 days. Anaerobic bacterial infections Child: <8 wk 7.5 mg/kg 12 hrly or 15 mg/kg once daily. 8 wk to 12 yr 7.5 mg/kg 8 hrly or 20-30 mg/kg once daily. Duration of treatment is usually for 7 days depending on the severity of infection. Prophylaxis of postoperative anaerobic bacterial infections Child: <40 wk 10 mg/kg as a single dose before surgery; <12 yr 20-30 mg/kg as a single dose 1-2 hr before surgery. Intravenous Anaerobic bacterial infections Child: 7.5 mg/kg 8 hrly.

Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Metronidazole is to be taken with food.

If you miss a dose of Metronidazole, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.

Common: • Headache • Dryness in mouth • Nausea • Metallic taste

[UNSAFE] Metronidazole may cause side effects which could affect your ability to drive. Metronidazole may make you feel sleepy, dizzy, confused. You may have hallucinations, fits (convulsions) or temporary eyesight problems (such as blurred or double vision) affecting your ability to drive. Metronidazole treats infections caused by bacteria and parasites. It may cause side effects like nausea, stomach upset, and a metallic taste in the mouth. Metronidazole used in a high dose or for a prolonged time increases the risk of side effects such as nerve damage. Take it only as prescribed by your doctor. Do not drink alcohol during or for 2-3 days after treatment with this medicine. You may develop nausea, vomiting, flushing and headache. Inform your doctor if you have liver disease. Your dose may need to be adjusted in severe liver disease.

History of hypersensitivity to metronidazole or other nitroimidazole derivatives. Pregnancy (1st trimester) and lactation.

Concurrent use w/ disulfiram may produce psychotic reactions. May potentiate the effect of oral anticoagulants. May increase risk of lithium toxicity. May reduce the renal clearance resulting to increased toxicity of 5-fluorouracil. May increase serum levels of ciclosporin. May increase plasma levels of busulfan resulting to severe busulfan toxicity. Enhanced metabolism w/ phenobarbital and phenytoin resulting to decreased serum concentrations.

[UNSAFE] Consuming alcohol while taking Metronidazole may cause symptoms such as flushing, increased heart beat, nausea, thirst, chest pain and low blood pressure (Disulfiram reaction).

[SAFE IF PRESCRIBED] Metronidazole is generally considered safe to use during pregnancy. Animal studies have shown low or no adverse effects to the developing baby; however, there are limited human studies.

[CAUTION] Metronidazole should be used with caution during breastfeeding. Breastfeeding should be held until the treatment of the mother is completed and the drug is eliminated from her body. If a single dose of Metronidazole is used, it is recommended to hold breastfeeding for 12-24 hours to allow the removal of the drug.

Metronidazole is safe for children, but the dose depends on body weight (30-50 mg/kg/day, divided every 8 hours). Dosage varies by age. Consult a pediatrician for the correct dose.

Use with caution in elderly patients, as liver and kidney function may decline. Dose adjustment may be necessary.

[SAFE IF PRESCRIBED] Metronidazole is safe to use in patients with kidney disease. No dose adjustment of Metronidazole is recommended. Patients undergoing kidney dialysis should take this medicine after the dialysis treatment. [CAUTION] Metronidazole should be used with caution in patients with liver disease. Dose adjustment of Metronidazole may be needed. Please consult your doctor.

Overdose (up to 12 g) may cause vomiting, ataxia, and slight disorientation. There is no specific antidote. Symptomatic and supportive treatment should be given in case of massive overdose.

Store below 30°C, protected from light. Keep out of reach of children. Do not use after the expiry date.

Molecular Formula: C₆H₉N₃O₃