Oseltamivir

When ATH:
J05AH02

Pharmacological action

Antiviral agent. It is a prodrug, active metabolite (oselytamivir carboxylate) which selectively inhibits influenza virus neuraminidase Types A and B. Neuraminidase is a glycoprotein, which catalyzes the cleavage of the link between terminal sialic acid and sugar, thereby contributing to the spread of the virus in the respiratory tract (output virions from infected cells and penetrate the epithelial cells of the respiratory tract, preventing the inactivation of the virus epithelial mucus). Oseltamivir carboxylate acts outside the cells, and competitively inhibits neuraminidase. It stops the growth of influenza virus in vitro and suppresses viral replication and pathogenicity in vivo. It reduces the allocation of influenza viruses A and B from the body.

No effect on the production of antibodies in response to inactivated influenza vaccine.

The frequency of resistant clinical isolates of the virus 2%.

Pharmacokinetics

Once inside almost completely absorbed from the gastrointestinal tract, not depend absorption of taking screaming. Обладает эффектом “первого прохождения” через печень. By intestinal and hepatic esterases converted to the active metabolite. 75% an oral dose reaches the systemic circulation as the active metabolite, less 5% – в виде исходного вещества. Plasma concentrations of both the prodrug, and the active metabolite are proportional to dose.

Average V_d активного метаболита – 23 l. Plasma protein binding - 3%.

Displays in the form of the active metabolite primarily by the kidneys by glomerular filtration and tubular secretion. T_1/2 осельтамивира – 1-3 no. Oseltamivir carboxylate is not further metabolized and excreted by the kidneys, his T_1/2 – 6-10 no. Почечный клиренс – 18.8 l /. Выводится через кишечник – менее 20%.

Elderly patients (65-78 years) concentration of the active metabolite in the equilibrium state at 25-35% higher, than in younger patients. In patients with renal insufficiency rate of excretion of oseltamivir carboxylate is inversely proportional to RC.

Testimony

Influenza types A and B.

Dosage regimen

Is the inside, regardless of the meal.

When receiving the treatment should start no later than 2 days from the time of disease symptoms in a dose of 75 mg 2 times / day for 5 days. Increasing the dose more 150 mg / day did not lead to increased effect.

Для профилактики гриппа типов А и В взрослым – по 75 mg 1-2 times / day for 6 Sun. (during a flu epidemic). The maximum dose для взрослых – 150 mg / day.

In patients with CC less than 30 ml / min dose reduce to 75 mg 1 times / day for 5 days.

Side effect

From the digestive system: nausea, vomiting (usually when taken in high doses, or in the first days of treatment); редко – диарея, stomach ache.

CNS: insomnia, dizziness, headache.

The respiratory system: nasal congestion, sore throat, cough.

Other: feeling tired, weakness.

Contraindications

Chronic renal failure (CC less than 10 ml / min), hepatic failure, Hypersensitivity to oseltamivir.

Pregnancy and lactation

C caution during pregnancy and lactation.

Cautions

C wary of children.

Patients with liver failure safety and effectiveness has not been established oseltamivir.

There are no data on the safety of oseltamivir in CC than 10 ml / min.

Drug Interactions

Drugs, block tubular secretion, in 2-3 times increase the concentration of the active metabolite (due to inhibition of active tubular secretion in the kidney), that does not require dose adjustments.