The antibiotic metronidazole is used to treat bacterial infections as well as diseases caused by protozoa (animal protozoa). Depending on the infection, it is available in the form of tablets, suppositories and infusions, as well as a cream, gel or ointment. Side effects such as headache, gastrointestinal discomfort, or skin redness may occur while taking metronidazole. Learn more about the effects, side effects, and dosage of metronidazole here.
How metronidazole works
Metronidazole is a prescription antibiotic that belongs to the nitroimidazole group. It is used to treat infections caused by anaerobic bacteria or protozoa. Active substances from the nitroimidazole group are metabolized by bacterial enzymes to form so-called nitroso radicals. These attack the DNA of the bacteria and lead to strand breaks. As a result, the cell dies and the infection can be effectively fought.
Fields of application of the antibiotic
Metronidazole is used to treat bacterial infections of the mouth and jaw, ear, nose, and throat, gastrointestinal tract (Helicobacter pylori), and female reproductive organs. Furthermore, it is also used in bone and joint and leg vein inflammations and in heart infections. In addition, the active ingredient can prevent infection during operations in the gastrointestinal tract and on the female genital organs. Metronidazole can also be used to treat inflammation of the vagina or the male urethra caused by trichomonads (flagellates). Transmission occurs primarily through sexual intercourse. Therefore, the sexual partner should also be examined for the pathogens and treated if necessary. Metronidazole can also be used to treat a number of other diseases, particularly those affecting the gastrointestinal tract and the female reproductive organs. These include the intestinal diseases lambliasis (giardiasis) and amoebiasis (amoebic dysentery), as well as bacterial vaginosis. As an ointment or cream, metronidazole is used to treat skin conditions such as rosacea or perioral dermatitis, as well as eczema and abscesses.
Side effects of metronidazole
Taking metronidazole can be associated with a wide variety of side effects. In addition to the dosage, the dosage form of the antibiotic is also crucial. Tablets, infusions, or suppositories:
Taking metronidazole can cause side effects such as inflammation of the mouth or tongue, taste disorders and tongue coating. Likewise, gastrointestinal symptoms such as diarrhea, abdominal pain, and nausea and vomiting may occur. It is also common for patients to experience a dark color to their urine during treatment. Occasionally, side effects such as headache, dizziness, sleep disturbances, weakness, drowsiness, numbness, tingling, depression, seizures, incoordination, and nervous disorders have been observed. In addition, blood count changes or phlebitis may occur. In rare cases, side effects such as allergic reactions and skin redness, bladder infections, urinary disorders and bladder weakness, genital fungal infections, visual disturbances and liver dysfunction may continue to occur. Local application to the gums:
If metronidazole is applied to the gums, it may increase tooth sensitivity. In rare cases, side effects such as reddening of the gums and inflammation of the gums as well as taste disorders may also occur. Furthermore, dizziness, difficulty swallowing, headache, nausea and vomiting, and skin reactions may occur. Local or vaginal use:
In rare cases, side effects such as redness, itching or burning may occur.
Dosage of metronidazole
Depending on the severity of the disease, the dosage of metronidazole may vary greatly. Therefore, the following dosage information is only a general guideline. You should always discuss the exact dosage with your treating physician. You should not take the antibiotic for more than ten days at a time without consulting your doctor. Uncomplicated infections can be treated by giving 0.2 grams of metronidazole three times or less for five to seven days. If the active ingredient is dosed higher (one to two grams), a period of one to three days may be sufficient.For complicated infections, between 1.6 and 2 grams of metronidazole are administered initially, followed by one gram each for five to seven days. Complicated infections include inflammation of the endometrium, ovaries and peritoneum, inflammation of the mouth and jaw, and inflammation of the ear, nose and throat.
Bacterial vaginosis and trichomoniasis.
Bacterial vaginosis or trichomoniasis may be treated in adults with as little as a single dose of two grams of metronidazole. Alternatively, for bacterial vaginosis, it is recommended to take one gram of the antibiotic at a time for seven days. This is usually done by taking two or three single doses daily. Following the same dosing schedule, a dose of between 0.8 and 1.6 grams of metronidazole can be administered for trichomoniasis. In children, the respective dose is determined individually by the treating physician depending on body weight and disease. Usually, children receive between 20 and 30 milligrams per kilogram of body weight. The maximum dose per day is 2 grams. Metronidazole should not be used to treat rosacea and periodontitis in children.
Contraindications
Metronidazole should not be used if there is hypersensitivity to the active ingredient. In addition, the antibiotic should be used in patients with severe liver disease only after a careful risk-benefit analysis. If the antibiotic is taken in tablet form, liver values must be monitored at regular intervals. Metronidazole may also only be used after a careful risk-benefit analysis in diseases of the nervous system – for example epilepsy -, the brain and spinal cord, and in blood formation disorders. In the case of defective blood composition, an individual decision must be made by the physician as to whether creams or ointments containing metronidazole may be used to treat rosacea.
Interactions
Similar to side effects, interactions also depend on the particular dosage form. Please clarify which interactions may occur in your case with your treating physician. Alternatively, a look at the package leaflet can also help you. In general, interactions may occur if metronidazole is taken with any of the following medications or active ingredients:
- Sleeping pills
- Curmarine derivatives
- Lithium
- Phenytoin
- Cimetidine
- Disulfiram
Patients treated with certain anticoagulants must be readjusted when taking metronidazole. This is necessary because the antibiotic can increase the anticoagulant effect of the drugs. You should avoid alcohol during treatment with metronidazole. Otherwise, interactions such as headache, dizziness, nausea, and vomiting may occur.
Pregnancy and breastfeeding
Metronidazole should not be taken during pregnancy. To date, it has not been possible to determine with certainty whether damage to the unborn child can occur as a result of the active substance. Therefore, especially in the first three months of pregnancy, the antibiotic should be resorted to only in the case of life-threatening infections. After that, the active substance may only be prescribed after a careful risk-benefit analysis. Whenever possible, ointments, creams or gels should be used instead of tablets. Metronidazole should also not be taken during breastfeeding if possible, as the active substance passes into breast milk. If it is absolutely necessary to take the drug, breastfeeding should not take place during this time. If only a gel is applied to the mouth area, it is not necessary to interrupt breastfeeding.
