SELTAVIR 45 CAPSULES

Indications

• Treatment of influenza in adults and children
• Prophylaxis of influenza in high-risk populations

Dosage

Children: Refer to established guidelines or the BNF for Children for specific dosing information, as it varies based on the child's age and weight.

Adults: Refer to established guidelines or the BNF for specific dosing information, as it varies based on the indication and patient condition.

Mechanism of action

Oseltamivir works by inhibiting the neuraminidase enzyme on the surface of the influenza virus. This enzyme is crucial for the virus's ability to replicate and spread from cell to cell. By blocking neuraminidase, oseltamivir prevents the release of new viral particles from infected cells, thereby limiting the spread of the virus within the respiratory tract.

Pharmacodynamics

The pharmacodynamics of oseltamivir involve its selective inhibition of the influenza neuraminidase enzyme, leading to a decrease in viral titers and an improvement in influenza symptoms. Oseltamivir is effective against both influenza A and B strains. It reduces the duration of symptoms and the severity of the illness, and it can also reduce the risk of complications associated with influenza.

Pharmacokinetics

Oseltamivir is well-absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1 to 2 hours after oral administration. It has a bioavailability of approximately 80%. The drug is primarily eliminated via the kidneys, with a half-life of about 6 to 10 hours. Its active metabolite, oseltamivir carboxylate, has a longer half-life and is responsible for the antiviral activity. Renal function can significantly affect the clearance of oseltamivir, necessitating dose adjustments in patients with renal impairment.

Contra-indications

• Hypersensitivity to oseltamivir or any of its components
• Severe renal impairment (CrCl < 10 mL/min)

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Headache
• Dizziness
• Fatigue

Interactions

• Probenecid may increase oseltamivir exposure
• Live attenuated influenza vaccine may be less effective if given within 2 weeks of oseltamivir

Precautions

• Use with caution in patients with renal impairment
• Monitor for neuropsychiatric events, especially in pediatric patients

Pregnancy

Oseltamivir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Oseltamivir is excreted in breast milk; caution should be exercised when administered to nursing mothers.

Storage

Store at room temperature (20-25°C). Protect from moisture. Keep out of reach of children.

Formulations

• Oseltamivir phosphate 30 mg capsule
• Oseltamivir phosphate 45 mg capsule
• Oseltamivir phosphate 75 mg capsule
• Oseltamivir phosphate 6 mg/mL oral suspension