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International Notes Eosinophilia-Myalgia Syndrome -- Canada

As of May 14, 1990, 10 confirmed cases of eosinophilia-myalgia syndrome (EMS) in Canada have been reported to the Laboratory Centre for Disease Control (LCDC), and other possible cases are under investigation. All 10 cases have been linked to use of L-tryptophan (LT)-containing pills. Eight of the confirmed cases are in females. Eight patients used single-ingredient dietary supplements purchased in the United States; one of the remaining patients obtained LT compounded from an unspecified bulk material at a Canadian pharmacy, and the other had obtained nonprescription LT manufactured in the United States and distributed illegally in Canada.

In Canada, single-ingredient LT products have been required to be sold by prescription since 1985. The prescription drug Tryptan*, manufactured by ICN Canada Ltd., is the only single-ingredient LT product legally available in Canada. No EMS cases have been directly linked to Tryptan.

Laboratory and epidemiologic investigations of EMS are under way. Physicians in Canada should report any cases meeting the case definition (1) to the Acting Director, Bureau of Chronic Disease Epidemiology, LCDC, Health and Welfare Canada, Ottawa, K1A 0L2 (telephone (613) 957-0329; FAX (613) 952-7009). Adapted from: Canada Diseases Weekly Report 1990;16:69-70, as reported by: K Wilkins, MSc, D Wigle, MD, Bur of Chronic Disease Epidemiology, Laboratory Centre for Disease Control, Health and Welfare Canada, Ottawa, Ontario.

Editorial Note

Editorial Note: As of May 11, 1990, 1500 EMS cases have been reported to CDC from state and territorial health departments in the United States. A total of 23 persons who had been taking LT before their illness have died.


  1. CDC. Eosinophilia-myalgia syndrome--New Mexico. MMWR 1989;38:765-7. *Use of trade names is for identification only and does not imply endorsement by the Public Health Service or the U.S. Department of Health and Human Services.

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