Neurological function during long-term therapy with recombinant interferon alpha

In 14 patients with myeloproliferative disorders associated with thrombocytosis, neurological and neuropsychological function were monitored prior to therapy with recombinant human interferon alpha (rIFN; dose 25 mU/week; range 10-35 mU/week) and after 3, 6, 9, and 12 months of treatment. No overt neurological side effects were observed except 1 case of cerebral insult, probably not treatment-related. Attention, memory function, and tapping improved significantly. The P2-N3 amplitudes of visually evoked potentials increased during normalization of platelet counts. Muscular strength and the amplitude of the compound muscle action potential of the median and peroneal nerves increased significantly in an inversely dose-related fashion. In patients with myeloproliferative disorders, long-term therapy with low to intermediate doses of rIFN does not seem to impair neurological function, but rather is associated with enhanced muscle power and the level of mental arousal.