Subacute myelo-optic neuropathy

Subacute myelo-optic neuropathy (SMON) is an iatrogenic disease of the nervous system leading to a disabling paralysis, blindness and even death. Its defining manifestation was as an epidemic in Japan during the 1960s: the Japanese government estimated 11,000 were affected; however, the College of Medicine at the University of Tokyo put the number at 30,000, citing a lack of preservation of medical records for longer than five years and a lack of cooperation from doctors as the reasons for the discrepancy. On August 3, 1978, the Tokyo District Court ruled that the cause of SMON is Clioquinol. Its manufacturer, Ciba-Geigy, has publicly stated that "Medical products manufactured and sold by us have been responsible for the occurrence of [SMON] in Japan, we extend our apologies."

SMON was first observed and diagnosed in Sweden 1966, by the pediatrician and neurologist Olle Hansson. Clioquinol was marketed as a prophylaxis to tourist diarrhoea. Dr. Olle Hansson was in the front line, fighting for a ban of clioquinol. Doctors in many countries boycotted Ciba-Geigy for many years. Not until 1985 was the pharmaceutical withdrawn. Dr Hansson died a few months later. The day of his death, May 23, is observed as the Anti-Hazardous Drug Day in several parts of the world.

Further reading

• Reisaku Kono, "Relation between Subacute Myelo-Optic Neuropathy (S.M.O.N.) and Clioquinol: Nationwide Survey", The Lancet, V301, I7796, January 27, 1973, pp. 171–173
• Reisaku Kono, "The S.M.O.N. Virus Theory", The Lancet, V306, I7930, August 23, 1975, pp. 370–371
• Reisaku Kono, Yoshigoro Kuroiwa, "Subacute Myelo-Optic Neuropathy is not a special form of multiple sclerosis", The Lancet, V320, I8292, July 31, 1982, p. 267
• Hansson, Olle: "Inside Ciba-Geigy". IOCU 1989. ISBN 967-9973-26-3.