Abstract
The aim of this study was to investigate the safety of oseltamivir in Japanese patients
less than 1 year of age infected with influenza A or B. The study was retrospective
and surveillance forms were used to collect safety data for all influenza-infected
infants administered oseltamivir during the 2003/2004 influenza season in the 157
participating facilities. Seven hundred seventy one children (mean age 272 ± 74.86
days, range 15 to 366 days) were treated with oseltamivir at a mean dose of 3.84 ±
0.51 mg/kg/day (range 1.85 to 6.25 mg). The incidence of adverse events (AEs) and
adverse drug reactions (ADRs) was 5.3% (41 of 771 patients) and 3.2% (25 of 771 patients),
respectively. Among the 51 AEs reported in 41 patients, gastrointestinal disorders
were the most frequent (2.5% [19 of 771 patients]), with diarrhoea (n = 15) and vomiting (n = 6). Gastrointestinal disorders were also the most frequently reported ADRs, with
diarrhoea (n = 13) and vomiting (n = 5). Four patients with afebrile or febrile convulsions (n = 3) and respiratory failure (n = 1) with fatal outcome were probably caused by serious AEs. Influenza infection
accompanying with high fever is well known to cause these events in infants. This
paper has concluded effective treatment of oseltamivir administration in influenza-infected
infants less than 1 year of age; and it does not raise any safety concerns. Therefore,
a further prospective survey to elucidate the ADRs should be carried out.
Keywords
Infant - under 1 year of age - oseltamivir - influenza virus - drug safety
