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August 23, 1976

SMON Probably Occurred in 1938 in Japan

Author Affiliations

Tokyo Medical and Dental University Medical Research Institute
University of Tokyo School of Health Sciences Tokyo

JAMA. 1976;236(8):919. doi:10.1001/jama.1976.03270090015014

To the Editor.—  One of the questions against the theory that iodochlorhydroxyquin causes subacute myelo-opticoneuropathy (SMON) was "Why has the disease become apparent only in the past decade when the drug has been used for four decades?" (220:273, 1972). In fact, reports of the outbreaks of SMON had appeared since 1958,1 although iodochlorhydroxyquin had been used orally from 19292 in Japan.To elucidate this problem, one of us (K. K.) studied the conditions of the use of iodochlorhydroxyquin before the Second World War through a review of the literature, especially the reports of clinical trials. Consequently, it was found that the daily doses were relatively small and the duration of administration short at that time. One of the reports published in 1938, however, stated that no adverse effect was observed when the drug was administered to 30 carriers of Salmonella typhi in a daily dose of 1.0 to