Neuropathy of nitroimidazole radiosensitizers: clinical and pathological description.

The dose limiting toxicity of the nitroimidazole radiosensitizers is peripherial neuropathy. Improved pharmacology of newer drugs has eliminated the encephalopathy. Peripheral neuropathies are predominently mild to moderate paresthesias of both hands and feet. Subjective changes occur with or without minimal objective changes on neurologic exam. All of the neuropathies occurred within 30 days of the last drug dose and are of variable duration. Sural nerve biopsies from patients indicate progressive axonal degeneration affecting both large and small caliber myelinated fibers. Axonal damage appears to be more severe in the distal portion of the nerves. More data are needed for correlation of clinical and pathological changes.