[The smaller number of influenza patients with neuropsychiatric events had taken oseltamivir beforehand].

UNLABELLED

Oseltamivir is a neuraminidase inhibitor preventing the release of the infectious influenza virus particles from the infected respiratory tract cells of the patients. It is known that the medicine reduces the duration and the severity of this infectious disease and the incidence of pneumonia as its complication. Recently some reports emerged mainly from Japan that neuropsyciatric events are provoked by oseltamivir. However, the neuraminidase inhibitor might be expected to prevent the events, as it reduces the viral burden. Therefore it was investigated whether oseltamivir reduces the incidence of the events.

PATIENTS AND METHODS

The study was conducted at the Yokohama Rosai Hospital, Kanagawa, Japan since December 2006 to March 2007. Patients with fever who had got the positive result of the influenza viral antigen test but no neuropsyciatric events, older than one year old, were enrolled in this study. The cases were the patients who visited the outpatient department of the hospital for their neuropsychiatric events (Case Group). The controls were the patients more than one year old with no neuropsychiatric events (Control Group). Nasopharyngeal aspirate fluid was used for detecting influenza virus by using a rapid diagnosis test, the ESPLINE Influenza A&B-N (Fujirebio Corp., Japan). The proportion of gender, age, and the use of oseltamivir were compared in the two groups with t-test and chi-squared test.

RESULTS

Twelve cases and 335 control patients were enrolled in this study. The mean age and its standard deviation of the Case Group was 8.25 +/- 3.22 years old, which was significantly higher than that of the Control Group (6.09 +/- 3.74 years old, p = 0.049). The Case Group consisted with 9 boys (75.0%) and 3 girls (25.0%), as the Control Group had 183 boys (54.6%) and 152 girls (45.4%). The frequency of the type A virus was not significantly higher in the Case Group (7 patients, 58.3%) than in the Control Group (168 patients, 50.1%) (p = 0.162). Six cases (50.0%) in the Case Group had taken oseltamivir prior to the neuropsychiatric events on the contrast that 261 patients (77.9%) in the Control Group were prescribed the same medicine; the difference was statistically significant (p = 0.024).

CONCLUSION

It is concluded that oseltamivir, an influenza virus neuraminidase inhibitor, significantly reduces the incidence of the neuropsychiatric events of the patients with influenza virus infection.