Influenza is a transmissible viral pathogen that continues to cause substantial morbidity and mortality.
Oseltamivir is an orally administered
antiviral medication that selectively inhibits the
influenza neuraminidase enzymes that are essential for viral replication. Treatment of infected children > or =1 year and adults of all ages may decrease the severity and duration of the symptoms of
infection, while prophylactic dosing can prevent their onset.
Oseltamivir is ingested in the form of a
prodrug (
oseltamivir phosphate) that is rapidly converted by hepatic
esterases into the active metabolite,
oseltamivir carboxylate.
Oseltamivir carboxylate has high bioavailability and penetrates sites of
infection at concentrations that are sufficient to inhibit viral replication. The pharmacokinetics of
oseltamivir and
oseltamivir carboxylate are dose proportional after repeated doses of up to 500 mg twice daily. This predictable profile means that
oseltamivir is suitable for use in diverse patient populations, which may include young children and elderly patients, various ethnic groups and those with renal or hepatic impairment. As the potential for drug interactions is low,
oseltamivir is also suitable for use in patients with co-morbid conditions who are likely to be receiving concomitant medications.