Oseltamivir - instructions for use, dose, side effects, contraindications

Oseltamivir - a prodrug, when administered orally, is hydrolyzed and converted to the active form - oseltamivir carboxylate. The mechanism of action of oseltamivir carboxylate is associated with inhibition of neuraminidase of influenza virus types A and B. Neuraminidase - surface glycoprotein of influenza virus is one of the key enzymes involved in the replication of influenza viruses A and B.

Neuraminidase catalyzes the cleavage of the link between terminal sialic acid and the sugar, thereby facilitating dissemination of the virus in the respiratory tract (yield virions from infected cells and penetrate the epithelial cells of the respiratory tract by preventing the inactivation of the virus epithelial mucus).

There are 9 antigenic subtypes of influenza A neuraminidase type A - N1, N2, and so on, which, along with 16 antigenic hemagglutinin subtypes - H1, H2 and so on, define different strains of the same virus type. In the human population, several strains of influenza type A virus with hemagglutinin 1-5 and neuraminidase 1 and 2 are circulating simultaneously, the main of which are H3N2 and H1N1.

With the inhibition of neuraminidase, the ability of viral particles to penetrate the interior of the cell, as well as the yield of virions from the infected cell, is violated, which results in limiting the spread of infection through the respiratory tract.

Pharmacokinetics:

It is well absorbed in the gastrointestinal tract. Bioavailability 79 ± 12%. The relationship with plasma proteins is 42%, oseltamivir carboxylate - very low (<3%). The volume of distribution of oseltamivir carboxylate after intravenous the introduction of 24 volunteers varied in the range from 23 to 26 liters, metabolized by esterases in the liver and mucosa of the gastrointestinal tract into the active metabolite, the half-life of oseltamivir 1-3 hours, the active metabolite 6-10 hours, excreted by the kidneys in the form of oseltamivir carboxylate (> 99 %). It is not removed during hemodialysis.

Indications:

Influenza A and B.

Treatment of influenza in adults and children over the age of 1 year. Prevention of influenza in adults and adolescents over 12 years of age who are at high risk of infection with the virus. Prevention of influenza in children older than 1 year.

ICD-10

X.J10-J18.J10 Influenza caused by an identified influenza virus

Contraindications:

Kidney disease (creatinine clearance less than 10 ml / min).

Hypersensitivity.

Diseases of the liver (liver failure).

Carefully:

Children up to 1 year.

Pregnancy and lactation.

Severe course of influenza.

Pregnancy and lactation:

Category FDA - C, use during pregnancy or lactating mothers with caution inIt is possible, if the expected effect of therapy exceeds the potential risk for the fetus or infant (adequate and strictly controlled studies of safety of use in pregnant and lactating women have not been conducted).

Dosing and Administration:

Orally, with meals or regardless of food intake.

Treatment: take the drug no later than 2 days from the moment of occurrence of symptoms of influenza; adults and children over 12 years - 75 mg 2 times a day, the course is 5 days. Children from 1 year to 12 years - depending on body weight. The maximum dose is 150 mg per day.

For the prevention of influenza in adults and children over 12 years: 75 mg once a day for 6 weeks (during the epidemic), the maximum daily dose - 150 mg.

In patients with creatinine clearance less than 30 ml / min a correction of the dose (75 mg once a day for 5 days); at ground clearance creatinine less than 10 ml / min no data on application.

In a dose of 75 mg twice a day for 5 days; an increase in the dose of more than 150 mg /day does not increase the effect.

Side effects:

On the part of the gastrointestinal tract: diarrhea, vomiting, nausea, abdominal pain, pseudomembranous colitis,

From the nervous system: headache, dizziness, insomnia, convulsions.

On the part of the respiratory system: sore throat, cough, nasal congestion, bronhitis, pneumonia,

Other: weakness, fatigue, conjunctivitis, hearing impairment, nosebleeds, unstable angina, anemia, fever, paratonzillar abscess, rash, increased activity of hepatic enzymes, hepatitis.

Overdose:

Nausea, vomiting, dizziness. Treatment is symptomatic.

Interaction:

Probenecid, which blocks tubular secretion, increases the concentration of the active metabolite of the drug in the blood by 2-3 times.

Special instructions:

It should be borne in mind that a serious bacterial infection can begin with influenza-like symptoms, accompany the flu or be its complication. Oseltamivir phosphate is not indicated to prevent such complications.

Serious skin reactions and hypersensitivity reactions. In post-marketing observations, when oseltamivir phosphate was used, rare cases of anaphylaxis and severe skin reactions, including toxic epidermal necrolysis, Stevens-Johnson syndrome, and erythema multiforme, were noted. If such reactions occur, you should stop taking oseltamivir and take appropriate treatment.

Impact on the ability to drive vehicles and manage mechanisms

Not found.

Instructions

Oseltamivir (Oseltamyvirum)