The protease inhibitor lopinavir-ritonavir may produce opiate withdrawal in methadone-maintained patients

Abstract

This study examines the pharmacokinetic/pharmacodynamic interactions between (1) lopinavir-ritonavir (L/ R), a fixed combination of protease inhibitors used for the treatment of HIV disease, and (2) ritonavir alone at the same dosage as that in the L/R formulation, with methadone, an opiate frequently used in substance abuse pharmacotherapy for opioid (heroin) -dependent injection drug users, many of whom are infected with HIV. L/R was associated with significant reductions in the methadone area under the concentration-time curve (P