Oseltamivir (Tamiflu®) and its potential for use in the event of an influenza pandemic

Abstract

Recent cross species transmission of avian influenza has highlighted the threat of pandemic influenza. Oseltamivir (Tamiflu) has been shown to be effective in the treatment and prevention of epidemic influenza infection in adults, adolescents and children (> or = 1 year). Although oseltamivir has not been approved for prophylactic use in children, it has been shown to be effective. Oseltamivir is also active against avian influenza virus strains. Evidence suggests that lower doses or shorter durations of treatment/chemoprophylaxis other than those approved may not be effective and may contribute to emergence of viral resistance. Safety data from dose ranging studies show that 5 day courses of 150 mg twice daily for treatment and 6 week courses of 75 mg twice daily for prophylaxis were as well tolerated as the approved dose regimens. The use of oseltamivir in a pandemic is influenced by the goals of the pandemic plan developed by the responsible Government and Health Authority. To optimize use of antiviral medications, processes will be needed to collect, collate and report outcome data from treated patients and/or from use for chemoprophylaxis of pandemic influenza during the first-wave outbreaks. If oseltamivir is included in a national or regional pandemic plan, stockpiling of the material, either in the form of capsules or the bulk active pharmaceutical ingredient will be necessary. In the absence of a stockpile, there is no guarantee that an adequate supply of oseltamivir will be available.

Pandemic influenza A (H1N1) 2009: the experience of the first six months

“…High dose oseltamivir (150 mg twice daily) and prolonged prophylaxis at normal treatment doses have been shown to be safe and well tolerated (62), and high dose treatment administered via nasogastric tube was shown to have a good pharmocokinetic profile in severe influenza A (H5N1) infection (63). No published data have shown high dose treatment to be more effective than treatment with normal doses (58).…”

“…No published data have shown high dose treatment to be more effective than treatment with normal doses (58). Oseltamivir is preferred over zanamivir for the treatment of pregnant women due to its systemic absorption (62,64).…”

Cutting Edge: Oseltamivir Decreases T Cell GM1 Expression and Inhibits Clearance of Respiratory Syncytial Virus: Potential Role of Endogenous Sialidase in Antiviral Immunity

“…BALB/c mice were infected with RSV as described above. The mice were given water or 10 mg/ kg/day oseltamivir by oral gavage 4 h preinfection and then every 12 h. Mice given 10 mg/kg/day of oseltamivir have plasma levels similar to humans given an oral dose of 75 mg twice daily (22).…”

Oseltamivir-Resistant Influenza Virus A (H1N1), Europe, 2007–08 Season

“…Limited development of resistance to oseltamivir has been observed in persons treated, with little evidence of onward transmission of resistant viruses (10), although low-level transmission of resistant variants cannot be discounted (11). However, oseltamivir-resistant viruses emerged in 18% (9/50) of treated Japanese children with infl uenza virus A (H3N2) infection and 16% (7/43) of treated Japanese children with infl uenza virus A (H1N1) infection, also with no evidence that these viruses transmitted effi ciently (12,13).…”