Roche says that new data from the USA and Japan shows there is no established causal link between neuropsychiatric symptoms and treatment with the firm’s antiviral Tamiflu.
The Swiss firm was responding to fears, especially coming from Japan, that the drug may induce fatal side effects. Two people who were taking Tamiflu (oseltamivir) fell to their deaths in the country last month, one of whom was a 14-year-old boy who plunged 30 metres from the 11th floor of an apartment block in Miyagino-ku, Sendai.
Roche said it is “aware that a number of reports have been received in Japan of neuropsychiatric symptoms including delirium, with associated abnormal behaviour, and very rare cases of death in patients suffering from influenza” who had also been taking the antiviral but added that "the Japanese Ministry for Health and Welfare stated that they see no causal relationship between these cases and Tamiflu."
The company also cited data from US health insurance records between 1999-2006 of over 101,000 patients treated with Tamiflu and over 225,000 not taking the drug which have shown that the former group “showed a lower likelihood of experiencing a central nervous system event such as delirium, delusion, confusion, hallucination, aggressive behaviour etc compared to those not receiving treatment.” A study carried out during the 2005/2006 influenza season by the JMHLW came to a similar conclusion.
The company added that influenza-associated delirium and neuropsychiatric disorders are not uncommon and occur in the USA in approximately four of every 100,000 influenza patients, resulting in hospitalisation and “the incidence in Japan is believed even higher.” A recent survey based on 1,219 Japanese paediatric patients reported abnormal behaviour in 1.7% of the patients and the company’s chief medical officer Eduard Holdener, declared that since the introduction of Tamiflu, “Roche has continuously monitored and reviewed post-marketing safety information and provides regular updates to the regulatory agencies."