Description
Metronidazole Pharmacodynamics
Antiprotozoal and antimicrobial drug, a derivative of 5-nitroimidazole. Mechanism of action consists in biochemical reduction of 5-nitrogroup by intracellular transport proteins of anaerobic microorganisms and protozoa; the reduced 5-nitrogroup interacts with deoxyribonucleic acid (DNA) of microorganism cells, inhibiting their nucleic acid synthesis, which leads to death of bacteria.
It is active against Trihomonas vaginalis, Entamoeba histolica, Gardnerella vaginalis, Giardia intestinalis, Lamblia spp. as well as obligate anaerobes Bacteroides spp. (including Bacteroides fragilis, Bacteroides distasonis, Bacteroides ovatus, Bacteroides thetaiotaomicron, Bacteroides vulgatus), Fusobacterium spp, Veillonela spp., Prevotella (P. bivia, P. buccae, P. disiens), and some gram-positive microorganisms (Eubacterium spp., Clostridium spp., Peptococcus spp., Peptostreptococcus spp.). The minimum suppressive concentration for these strains is 0.125-6.25 µg/ml.
In combination with amoxicillin it shows activity against Helicobacter pylori (Amoxicillin suppresses development of resistance to metronidazole).
Aerobic microorganisms and facultative anaerobes are not sensitive to metronidazole, but in the presence of mixed flora (aerobes and anaerobes) metronidazole acts synergistically with antibiotics and is effective against common aerobes.
It increases the sensitivity of tumors to radiation, causes sensitization to alcohol (disulfiram-like effect), stimulates reparative processes.
strains is 0.125-6.25 µg/ml. In combination with amoxicillin it shows activity against Helicobacter pylori (amoxicillin suppresses the development of resistance to metronidazole).
Aerobic microorganisms and facultative anaerobes are not sensitive to metronidazole, but in the presence of mixed flora (aerobes and anaerobes) metronidazole acts synergistically with antibiotics effective against common aerobes.
Indications
– Protozoal infections: extraintestinal amoebiasis (including amebic liver abscess), intestinal amoebiasis (amebic dysentery), trichomoniasis.
– Infections caused by Bacteroides spp. (including B. fragilis, B. distasonis, B. ovatus, B. thetaiotaomicron, B. vulgaris); bone and joint infections; central nervous system (CNS) infections, including meningitis, brain abscess; bacterial endocarditis; pneumonia, empyema and lung abscesses; sepsis.
– Infections caused by Clostridium spp., Peptococcus niger, Peptostreptococcus spp.: abdominal infections (peritonitis, liver abscess), pelvic infections (endometritis, fallopian tube and ovarian abscess, vaginal infections).
– Pseudomembranous colitis associated with antibiotic use.
– Gastritis or duodenal ulcer associated with Helicobacter pylori (as part of complex therapy).
– Prevention of postoperative complications (especially after operations on the colon, pararectal area, appendectomy, gynecological operations).
Contraindications
Hypersensitivity to metronidazole, to other nitroimidazole derivatives, to imidazoles and to other components of the drug;
Organic CNS lesions (including epilepsy);
Leukopenia (including in anamnesis);
Liver failure (in case of high doses);
Pregnancy;
Breast-feeding period;
Childhood under 6 years of age.
Caution
Hepatic encephalopathy;
Acute and chronic peripheral and central nervous system disorders (risk of increased neurological symptoms);
Renal insufficiency.
Use in pregnancy and during breastfeeding Pregnancy
Since metronidazole crosses the placental barrier and its effect on human fetal organogenesis is unknown, use of Metronidazole during pregnancy is contraindicated.
Breastfeeding period
Metronidazole penetrates into the breast milk, therefore the use of Metronidazole during breastfeeding is contraindicated.
Dosage and administration
- Metronidazole is taken orally, before or after a meal, with plenty of water.
- In intestinal amebiasis, metronidazole is used in a daily dose of 1500 mg (divided into 3 doses) for 7 days.
- In acute amebic dysentery, the daily dose is 2250 mg (divided into 3 doses). In children from 6 to 15 years of age, a daily dose of 500 mg (divided into 2 doses) is prescribed.
- In liver abscess and other extraintestinal forms of amebiasis, the maximum daily dose is 2500 mg (divided into 3 doses) for 3-5 days, in combination with tetracycline antibiotics and other therapies. Children 6 to 15 years of age are prescribed a daily dose of 500 mg (divided into 2 doses).
- In trichomoniasis in women (urethritis and vaginitis) metronidazole is indicated as a single dose of 2 g or as a course treatment of 250 mg twice daily for 10 days.
- In trichomoniasis in men (urethritis) metronidazole is prescribed as a single dose of 2 g or as a course treatment of 250 mg 2 times daily for 10 days.
- Treatment of anaerobic infections usually begins with intravenous infusions followed by conversion to tablets. For adults, the drug dose is 500 mg 3 times a day. The duration of treatment is up to 7 days.
- For treatment of pseudomembranous colitis, metronidazole is prescribed 500 mg 3-4 times a day. The duration of treatment is determined by the doctor.
- In eradication of Helicobacter pylori, metronidazole is prescribed 500 mg 3 times daily as part of combined therapy (for example, with amoxicillin).
- For prevention of postoperative complications, metronidazole is prescribed in a daily dose of 750-1500 mg (divided into 3 doses) 3-4 days before surgery. One to two days after surgery (when oral administration is already allowed), metronidazole is prescribed at 750 mg for 7 days.
