Possible Interaction Between Vidarabine and Theophylline

Excerpt

To the editor: Vidarabine's major metabolite is hypoxanthine arabinoside. The metabolite is excreted renally and biotransformed via the xanthine oxidase pathway (1, 2). Theophylline is metabolized by the hepatic miscrosomal enzymes and xanthine oxidase (3). We suspect that when vidarabine and theophylline are used concomitantly, theophylline metabolism is inhibited.

A 62-year-old woman weighing 45 kg was admitted with suspected intraabdominal sepsis. She had a history of congestive heart failure and chronic obstructive pulmonary disease. Therapy was begun with ampicillin, gentamicin, clindamycin, digoxin, and intravenous aminophylline. Sepsis was due to Clostridia perfringens from a perforated gallbladder. The patient's therapy was eventually