Treatment of varicella zoster virus infections with adenine arabinoside

23 patients with complicated varicella zoster virus infections were treated with adenine arabinoside. Of 14 patients with herpes zoster, 13 had malignancy treated with irradiation and cytotoxic agents or steroids. Although the duration of active vesicle formation in these patients ranged from 2 to 14 days before therapy, no new lesions appeared after the fourth day of treatment with adenine arabinoside. Zoster encephalitis developed in 1 patient on the third day of treatment, and severe postherpetic neuralgia was seen in 3 patients. Of 9 treated patients with primary varicella, 6 improved, including 5 with evidence of varicella pneumonia. 2 of the 3 patients with varicella who died were immunosuppressed and had progressive viral pneumonia with persistently high titers of virus in vesicular fluid; the third patient was a child with Reye's syndrome. Double blind controlled studies will be necessary to demonstrate the efficacy of adenine arabinoside in the treatment of infections with varicella zoster virus.