Somatosensory deficits in monkeys treated with misonidazole

Misonidazole, a hypoxic cell radiosensitizer, can produce peripheral sensory disorders in humans. It has been studied in monkeys with a computer-controlled system for evaluating vibration sensitivity. Monkeys were trained to report when vibration was stimulating the finger tip. Sinusoidal vibrations of several frequencies were presented. Two monkeys were dosed with misonidazole and their vibration sensitivity tested. They received a dose of 3 g/m/sup 2/ (about 180 mg/kg) twice weekly over a period of 6 to 10 weeks. An amplitude-frequency detection function was determined for each monkey before and after drug treatment. An analysis of covariance comparing polynomial regressions was performed. A significant difference (p < 0.001) was found between control and experimental curves in both monkeys. Pharmacokinetic data indicated a half-life of the drug in blood of about 4 to 5 hr. The overall half-life for elimination did not increase throughout prolonged treatment with msonidazole. Neither motor nor sensory nerve conduction velocity was reduced after treatment.