Metronidazole, tablets 250 mg, 20 pcs.

An antiprotozoal and antimicrobial drug, a derivative of 5-nitroimidazole. Mechanism of action consists in biochemical reduction of 5-nitrogroup of metronidazole by intracellular transport proteins of anaerobic microorganisms and protozoa. The reduced 5-nitrogroup of metronidazole interacts with the DNA of the microbial cell, inhibiting the synthesis of their nucleic acids, which leads to the death of the bacteria.

It is active against protozoa: Trichomonas vaginalis, Giardia intestinalis, Entamoeba histolytica, Lamblia spp. as well as obligate gram-negative anaerobes: Bacteroides spp. (including Bacteroides fragilis, Bacteroides distasonis, Bacteroides ovatus, Bacteroides thetaiotaomicron, Bacteroides vulgatus), Fusobacterium spp., Gardnerella vaginalis, Veillonella spp, Prevotella spp. (Prevotella bivia, Prevotella buccae, Prevotella disiens) and some gram-positive anaerobic microorganisms: Eubacterium spp., Clostridium spp., Peptococcus spp., Peptostreptococcus spp., Mobiluncus spp. The minimum suppressive concentration for these strains is 0.125-6.25 µg/ml.

The aerobic microorganisms are insensitive to metronidazole.

PHARMACOKINETICS

Assimilation

After intravaginal administration it undergoes systemic absorption (about 56%). The relative bioavailability of metronidazole in the form of vaginal gel is 2 times greater than the bioavailability of vaginal tablets in a single dose of 500 mg. C_max when using vaginal gel is 237 ng/mL and is reached after 6-12 hours.

Distribution

The binding to plasma proteins is less than 20%. Metronidazole penetrates into most body tissues, through the BBB and the placental barrier. It is excreted with breast milk.

Metabolism

Metabolized in the liver by hydroxylation, oxidation and glucuronidation. The activity of the main metabolite (2-oxymetronidazole) is 30% of the activity of the parent compound.

When taking metronidazole in dosage form for systemic use 60-80% of the dose is excreted by the kidneys (20% of this amount is in unchanged form), through the intestine 6-15%.

Indications

Active ingredient

Composition

Active ingredient:

metronidazole 0.25 g

How to take, the dosage

In case of amebiasis Metronidazole is prescribed orally in adults for 7 days – 1.5 g/day in 3 doses;
in children – 30-40 mg/kg/day, also in 3 doses

. In case of giardiasis the preparation is prescribed for 5 days – adults 750-1000 mg per day, children of 2-5 years old – 250 mg per day, children of 5-10 years old – 375 mg per day, children of 10-15 years old – 500 mg per day. Take after a meal 2-3 times a day.

In case of trichomoniasis in women (urethritis and vaginitis) Metronidazole is indicated as a single dose of 2 g or as a course treatment for 10 days: 1 tablet (250 mg) 2 times a day. In parallel with oral administration, 1 vaginal suppository or vaginal tablet containing 250 mg of metronidazole is prescribed in the evening.

To exclude possible reinfection it is necessary to treat sexual partners at the same time.

The course of treatment is repeated in 4-6 weeks if necessary.

In case of trichomoniasis in men (urethritis) Metronidazole is indicated as a single dose of 2 g or as a course of treatment for 10 days with 1 tablet (250 mg) 2 times a day.

In case of non-specific vaginitis, 500 mg of Metronidazole is used 2 times a day for 7 days.

In the treatment of anaerobic infections we use Metronidazole at the rate of 1-1.5 g for adults,
for children at the rate of 20-30 mg/kg per day.

Interaction

In concomitant use of metronidazole with indirect anticoagulants increased prothrombin formation time is noted.

In concomitant use of metronidazole with preparations of lithium salts an increase in plasma lithium concentration and development of intoxication symptoms may occur.

Special Instructions

It should be taken into account that ethanol intake is contraindicated during the use of the drug, as a disulfiram-like reaction may develop (spastic abdominal pain, nausea, vomiting, headache, sudden rush of blood to the face).

The blood count should be monitored during long-term therapy.

In case of leukopenia the possibility of continuing treatment depends on the risk of developing an infectious process.

The drug should be discontinued if neurological symptoms develop.

When treating trichomonas vaginitis in women and trichomonas urethritis in men it is necessary to abstain from sexual activity. Simultaneous treatment of sexual partners is mandatory. During menstruation, treatment should be continued. After the end of trichomoniasis treatment, control tests should be done for 3 consecutive cycles before and after menstruation.

After treatment of giardiasis has ended (if symptoms persist) 3 stool examinations should be carried out after 3-4 weeks at intervals of several days (some successfully treated patients may have lactose intolerance caused by the infestation for weeks or months, resembling the symptoms of giardiasis).

The drug may immobilize treponemes and lead to a false-positive Nelson’s test.

It is not recommended to combine with nondepolarizing myorelaxants (e.g., vecuronium bromide).

Pediatric use

It is not recommended to use the drug in combination with amoxicillin in patients under 18 years of age.

Contraindications

With caution, use in the second and third trimesters of pregnancy.

Side effects

Allergic reactions: urticaria, skin rash.

Local reactions: burning sensation or irritation of the penis in the sexual partner, burning sensation or increased frequency of urination, vulvitis (itching, burning pain or hyperemia of the mucous membrane in the area of the external genitalia). After discontinuation of the drug, vaginal candidiasis may develop.

Systemic reactions: change in taste, including a “metallic” taste, dizziness, headache, dry mouth, nausea, vomiting, decreased appetite, spastic abdominal pain, constipation or diarrhea, dark coloring of urine, leukopenia or leukocytosis are possible.

Similarities