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. It has the effect of “first pass” through the liver. By intestinal and hepatic esterases converted to the active metabolite. 75% an oral dose reaches the systemic circulation as the active metabolite, less 5% – as starting material. Plasma concentrations of both the prodrug, and the active metabolite are proportional to dose.
Average Vd aktivnogo metabolite – 23 l. Plasma protein binding – 3%.
Displays in the form of the active metabolite primarily by the kidneys by glomerular filtration and tubular secretion. T1/2 oseltamivir – 1-3 no. Oseltamivir carboxylate is not further metabolized and excreted by the kidneys, his T1/2 – 6-10 no. Renal clearance – 18.8 l /. Displayed through the intestine – less 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.
For the prevention of influenza types A and B in adults – by 75 mg 1-2 times / day for 6 Sun. (during a flu epidemic). The maximum dose for adults – 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); rarely – diarrhea, 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.
