Acyclovir pharmacokinetics in plasmapheresis.

During experimental treatment of human immunodeficiency virus (HIV-1) infection using high doses of acyclovir (ACV) (600 mg IV every 8 h), cyclosporin, and several courses of plasmapheresis (PE) (60 ml/kg), ACV pharmacokinetics in three patients have been measured. The results with or without PE were not significantly different: half-time of elimination 3 vs. 2.3 h, volume of distribution 1.8 vs. 1.14 liter/kg, and total clearance 404 vs. 314 ml/min. The clearance and the fraction of elimination due to PE were 5.27 ml/min and 2.5%, respectively. These findings suggest that supplemental doses of ACV are not needed when plasmapheresis is performed.