Study discounts Tamiflu tie to psych problems

A review of a large US medical claims database provides no evidence of an increased incidence of abnormal behavior or psychiatric problems in people treated with Roche’s anti-flu drug Tamiflu, researchers say.

However, an analysis looking at specific disorders of the central nervous system revealed a significantly higher rate of “episodic” mood disorder among people with the flu who took Tamiflu, also called oseltamivir, compared with those who did not take an antiviral medication.

The review was conducted by Dr. James R. Smith, of Hoffman-La Roche in Basel, Switzerland, who provided funding for the study, and Dr. S. Sacks, of Hoffman-La Roche in Nutley, New Jersey.

In recent years, there have been case reports of psychiatric events occurring generally within 48 hours of the start of flu symptoms and the start of treatment with Tamiflu, particularly in children younger than 16 years.

This prompted the Food and Drug Administration in 2006 to add a precaution to the label of the influenza drug stating that patients with influenza should be closely monitored for signs of abnormal behavior immediately after starting Tamiflu.

In a look-back study, Drs. Smith and Sacks searched medical claims data for indications of psychiatric “events” in 60,267 influenza patients dispensed Tamiflu between November 1999 and April 2005. The investigators also evaluated another 175,933 influenza patients who were not dispensed an antiviral during the same period.

Tamiflu, they report in the International Journal of Clinical Practice, “did not appear” to increase the risk for any neuropsychiatric condition or for the vast majority of the individual central nervous system diagnoses evaluated.

However, in people aged 17 and younger, the rate of “episodic mood disorders” was higher in those who took Tamiflu relative to those who did not. The absolute rate was 0.22 percent with Tamiflu versus 0.12 percent with no antiviral drug therapy.

SOURCE: The International Journal of Clinical Practice, April 2009.