News of the Day ... In Perspective12/6/2006
Tamiflu may be linked to risk of self-injury and delirium; vitamin D suggested for influenza
New safety labeling provisions for the anti-influenza drug oseltamivir phosphate (Tamiflu) warn of potential neuropsychiatric adverse effects.
The warning is based on postmarketing reports, primarily from Japan, suggesting that persons who receive Tamiflu, especially children, may be at increased risk of self-injury or delirium.
An alert sent by MedWatch, the FDA’s safety information and adverse event reporting system, advised close monitoring of patients given Tamiflu for signs of abnormal behavior.
Tamiflu is indicated for prophylaxis of influenza and treatment of acute uncomplicated illness in those who have been symptomatic for no longer than two days. It is approved for patients one year of age and older. (MedScape Medical News 11/14/06).
Adverse events can be reported to MedWatch by telephone at (800) FDA-0178, online at www.fda.gov/medwatch, or by mail to 5600 Fishers Lane, Rockville, MD 20852-9787.
Some scientists suggest that a shortage of vitamin D triggers outbreaks of influenza, which tend to peak between late December and March.
Attempts to demonstrate a link between cold exposure and influenza susceptibility have failed. Additionally, influenza also occurs in tropical climes, where the seasonal pattern is similar. Some scientists hypothesize that sun exposure is the key. Susceptibility to influenza may be increased when vitamin D levels are lower, as during the rainy season in the tropics or winter in temperate zones.
Dr. John Cannell, a psychiatrist at Atascadero State Hospital in California noted that his ward at a maximum-security facility for the criminally insane was the only one spared during an influenza outbreak in April 2005. The only difference he could determine was that his 32 patients were taking high daily doses of vitamin D.
The hypothesis should be easy to prove or disprove with a controlled study. In the meantime, Cannell takes 5,000 IU of vitamin D daily during winter months (Michael Stroh, Baltimore Sun 11/26/06).