Neurotoxity of iodoxyquinoline: a further study on beagle dogs.

Eight beagle dogs were treated orally with iodoxyquinoline (chinoform, clioquinol) again, and all of them manifested similar neurologic symptoms to those observed in our previous experiments on mongrel dogs, beagle dogs, cats and a monkey. The neurologic symptoms were identical both clinically and pathologically with those of subacute myelo-optico-neuropathy (abbreviated to SMON) in man. In the present study, the neurologic manifestations evolved with less total chinoform doses (5.1-13.8 g/kg) in shorter periods (19-47 days) and there was no difference between each group on the increasing dosage and on fixed dosage. It is discussed in the present paper that onset of the neurologic symptoms is associated with unconjugated chinoform levels in the blood.