PURPOSE: To assess the effects of venlafaxine extended-release (XR) capsules and 
desvenlafaxine extended-release (XR) tablets upon indinavir pharmacokinetic 
properties when co-administrated to healthy volunteers.
METHODS: This was an open-label, two-period, fixed-dose study conducted at the 
clinical research unit located on a university campus. Twenty-four healthy 
volunteers enrolled in the study (mean age 28.3 ± 8.0 years). Each subject 
received a single dose of indinavir 800 mg on day 1. Subsequently, subjects were 
then randomly assigned to either the venlafaxine XR group (N = 12) or the 
desvenlafaxine XR group (N = 12). Starting on day 2, venlafaxine XR was dosed at 
37.5 mg/day for 4 days and increased to 75 mg/day for 6 days. Desvenlafaxine XR 
was dosed at 50 mg/day for 10 days. On day 12, indivanvir 800 mg was 
co-administered to both the venlafaxine XR and the desvenlafaxine XR groups. The 
pharmacokinetics of indinavir were determined both before and at the end of 
antidepressant dosing. Plasma indinavir, venlafaxine, and desvenlafaxine 
concentrations were assayed by high-performance liquid chromatography with 
ultra-violet (UV) detection. Indinavir pharmacokinetic parameters were 
calculated by noncompartmental analysis using validated computer software.
RESULTS: Venlafaxine XR and desvenlafaxine XR did not produce any significant 
changes in indinavir disposition. Both antidepressants were well tolerated by 
the subjects with only minor adverse side effects.
CONCLUSIONS: No pharmacokinetic drug-drug interaction was demonstrated between 
venlafaxine XR and indinavir or between desvenlafaxine XR and indinvair. The 
lack of interaction could be due to the venlafaxine and desvenlafaxine 
extended-release formulation.