Neurotoxic and other side effects of high-dose interferon in amyotrophic lateral sclerosis

6 patients with amyotrophic lateral sclerosis were treated with intravenous infusion of 100-200 million IU per day of human leukocyte interferon. Side effects of treatment included fever, chills, malaise, nausea, marked leukopenia, mild anemia, and thrombocytopenia. Tiredness, confusion, papilledema, and overall signs of acute encephalitis were observed. Tendon reflexes and muscle force decreased. EEG activity was slowed, and evoked potentials showed significant slowing of conduction times. Neuropsychological tests revealed congitive dysfunction. The syndrome of inappropriate antidiuretic hormone secretion developed in all patients. All side effects were reversible with cessation of interferon treatment.