Metronidazole: Price, Dosage & Where to Buy

Metronidazole is an antibacterial and antiprotozoal medicine used to treat infections caused by susceptible anaerobic bacteria, which are bacteria that can live without oxygen. It is also used for certain parasitic infections, including trichomoniasis and amoebiasis, and is available in several oral, topical, vaginal and intravenous forms. Metronidazole requires a prescription in the United Kingdom.

Metronidazole tablets treat confirmed trichomoniasis, a sexually transmitted infection caused by the parasite Trichomonas vaginalis. The label includes infections with symptoms and certain infections without symptoms associated with inflammation or erosion of the cervix. Treatment of sexual partners may be needed to prevent reinfection.

Tablets also treat intestinal amoebiasis, including amoebic dysentery, and amoebic liver abscesses; an abscess may still require drainage. Other indications include serious infections caused by susceptible anaerobic bacteria in the abdomen, skin, female reproductive organs, bloodstream, bones and joints, brain and surrounding membranes, lower respiratory tract, and heart lining.

Some infections require surgery or additional antibiotics alongside metronidazole. These tablet indications should not be assumed to apply to every formulation.

Metronidazole acts against certain bacteria and single-celled parasites. Inside susceptible organisms, the medicine is converted into active substances that damage their genetic material, called DNA. This interferes with the processes the organisms need to survive and multiply.

Its antibacterial activity is particularly relevant to anaerobic bacteria, which can live in environments without oxygen. Different organisms have different susceptibility to the medicine, so it does not treat every type of infection. In mixed bacterial infections, an additional antibiotic may be needed to cover organisms outside its range of activity.

The label lists oral tablets in strengths of 125 mg, 250 mg and 500 mg, oral capsules of 375 mg, and extended-release tablets of 750 mg. Other forms include oral suspension, skin preparations, vaginal gel and intravenous solutions. The label lists 250 mg three times daily for seven consecutive days as a trichomoniasis regimen for females, with treatment individualised.

The label lists 750 mg orally three times daily for 5 to 10 days for adult acute intestinal amoebiasis. The label lists 500 mg or 750 mg orally three times daily for 5 to 10 days for adult amoebic liver abscess. The label lists 7.5 mg/kg every six hours for adult oral treatment of serious anaerobic infections, with a maximum of 4 g during a 24-hour period.

The label lists a 50% dose reduction for severe hepatic impairment. Serious anaerobic infections usually receive intravenous treatment initially, and haemodialysis may require an individualised adjustment. These are label facts, not a personal treatment plan.

A missed dose can interrupt the planned treatment schedule. General pharmacy guidance is to resume the prescribed schedule when remembered unless the next dose is nearly due, in which case the missed dose is omitted.

Doses should not be doubled to compensate. A pharmacist can clarify the appropriate approach for the particular formulation and prescription.

Metronidazole crosses the placenta, and its effects on human fetal organ development are not known. There are no adequate, well-controlled studies in pregnant women. Most published studies did not show an increased risk of congenital abnormalities or other adverse fetal outcomes; a reported association with cleft lip was not confirmed.

For trichomoniasis, tablets are contraindicated during the first trimester, and the one-day regimen should not be used during pregnancy when alternative treatment has been inadequate. The label does not specify breastfeeding information. Discuss pregnancy or breastfeeding with a doctor or pharmacist.

The tablet label specifies controlled room-temperature storage and protection from light. Keep the medicine in its original packaging and out of the sight and reach of children. Follow the storage directions on the particular product's label to maintain quality.