Affiliations: Tahara Clinic, Yamaguchi, Japan | Teikyo University School of Medicine, Tokyo,
Japan | Enjudo Sugiur Iin (Clinic for Children), Aichi,
Japan | National Center for Child Health and Development,
Tokyo, Japan
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
