Oseltamivir

Oseltamivir is an antiviral drug that is active against influenza viruses of types A and B. Other trade names of the drug are Tamiflu, Flustop.

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Indications Oseltamivir

The drug is prescribed for the treatment of patients infected with influenza viruses of types A and B, and can be used to prevent infection with this virus during seasonal flu epidemics.

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Release form

Capsules of 75 mg, powder for suspension in a bottle (with a dispenser).

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Pharmacodynamics

The therapeutic effect of Oseltamivir is based on the suppression of enzyme activity on the surface of the influenza virus virion. In the body, the active substance of the drug oseltamivir phosphate is transformed into an active metabolite - oseltamivir carboxylate, which selectively inhibits neurominidase - a glycosidase enzyme-antigen of the cellular membranes of influenza viruses. As a result, the process of replication of viral cells and their reproduction in the affected target cells of the respiratory tract mucosa stops.

According to clinical studies, if this drug is taken within 36 hours after the onset of flu symptoms, the duration of the disease is reduced by almost 30%, and the severity of symptoms and the likelihood of complications are reduced by 40%.

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Pharmacokinetics

90% of oseltamivir phosphate, absorbed in the gastrointestinal tract, is metabolized into oseltamivir carboxylate, which enters the systemic bloodstream; 3% of the substance binds to plasma proteins. Bioavailability is 75-80%.

The half-life of the drug from plasma is on average 120 minutes. Oseltamivir carboxylate is excreted from the body by the kidneys (80%) and intestines (20%); the half-life can range from 6 to 10 hours.

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Dosing and administration

Oseltamivir should be taken orally (regardless of meals). For the treatment of influenza, it is recommended to take one capsule (75 mg) - twice a day; the course of treatment is 5 days. The dosage of the suspension is similar. For the prevention of influenza, take 75 mg once a day, the duration of use of the drug after contact with patients with influenza is 10 days (the preventive effect of the drug lasts only during its use).

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Use Oseltamivir during pregnancy

The use of Oseltamivir during pregnancy and lactation is not recommended, since the safety of this drug for the treatment of pregnant women has not been studied.

Contraindications

The use of oseltamivir is contraindicated in cases of weakened immunity, severe renal failure, chronic respiratory and cardiovascular pathologies, as well as in children under 12 years of age.

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Side effects Oseltamivir

The most common side effects of Oseltamivir are general weakness, headaches and dizziness; catarrhal phenomena (rhinorrhea, swelling of the nasal mucosa, sore throat, cough); nausea, vomiting, diarrhea, abdominal pain; sleep disorders, convulsions; allergic reactions (urticaria, bronchospasm, conjunctivitis); nosebleeds, cardiac arrhythmia, increased activity of liver enzymes. Hallucinations and mental disorders are possible.

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Overdose

Cases of overdose have not been described. The most likely manifestation of exceeding the therapeutic dose is an increase in the side effects of the drug. Symptomatic treatment should be used.

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Interactions with other drugs

Concomitant administration of Oseltamivir with drugs such as methotrexate, phenylbutazone and chlorpropamide is undesirable due to the possible slowdown in the elimination of their metabolites from the body.

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Storage conditions

Keep out of reach of children at temperatures up to +25ºС.

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Shelf life

Shelf life: 24 months.

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