Microbiologic assays and neurological toxicity during use of adenine arabinoside in humans

Patients with herpesvirus infections were given intravenous injections of 10-20 mg of adenine arabinoside (ara-A)/kg per day. When given the higher dosage, some patients with chronic hematologic conditions showed mild to moderate additional depressions in the level of hemoglobin. The number of neutrophils and platelets did not decrease, even when numbers were low at the onset of treatment with ara-A. Two patients with Hodgkin's disease who received 20 mg of ara-A/kg per day developed a transient motor aphasia resembling akinetic mutism. With the regimens of ara-A used and challenge inocula of approximately 50 plaque-forming units of virus, the minimal inhibitory concentrations of ara-A and hypoxanthine arabinoside for herpesviruses are usually not achieved in serum but may be attained in body fluids (urine and vesicular fluid). Antiviral activity in vesicular fluids is likely to involve a combination of ara-A, hypoxanthine arabinoside, and interferon.