Lack of a pharmacokinetic drug-drug interaction with venlafaxine extended-release/indinavir and desvenlafaxine extended-release/indinavir
ABSTRACT 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.
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.
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.
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.
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ABSTRACT: In order to anticipate drug-interactions of potential clinical significance the ability of the novel antidepressant, venlafaxine, to inhibit CYP2D6 dependent imipramine and desipramine 2-hydroxylation was investigated in human liver microsomes. The data obtained were compared with the selective serotonin re-uptake inhibitors, fluoxetine, sertraline, fluvoxamine and paroxetine. Venlafaxine's potential to inhibit several other major P450 s was also studied (CYP3A4, CYP2D6, CYP1A2). Ki values for venlafaxine, paroxetine, fluoxetine, fluvoxamine and sertraline as inhibitors of imipramine and desipramine 2-hydroxylation were determined from Dixon plots of control and inhibited rate data in human hepatic microsomal incubations. The inhibitory effect of imipramine and desipramine on liver microsomal CYP2D6 dependent venlafaxine O-demethylation was determined similarly. Venlafaxine's IC50 values for CYP3A4, CYP1A2 CYP2C9 were determined based on inhibition of probe substrate activities (testosterone 6 beta-hydroxylation, ethoxyresorufin O-dealkylase and tolbutamide 4-hydroxylation, respectively). Fluoxetine, paroxetine, and fluvoxamine were potent inhibitors of imipramine 2-hydroxylase activity (Ki values of 1.6 +/- 0.8, 3.2 +/- 0.8 and 8.0 +/- 4.3 microM, respectively; mean +/- s.d., n = 3), while sertraline was less inhibitory (Ki of 24.7 +/- 8.9 microM). Fluoxetine also markedly inhibited desipramine 2-hydroxylation with a Ki of 1.3 +/- 0.5 microM. Venlafaxine was less potent an inhibitor of imipramine 2-hydroxylation (Ki of 41.0 +/- 9.5 microM) than the SSRIs that were studied. Imipramine and desipramine gave marked inhibition of CYP2D6 dependent venlafaxine O-demethylase activity (Ki values of 3.9 +/- 1.7 and 1.7 +/- 0.9 microM, respectively). Venlafaxine did not inhibit ethoxyresorufin O-dealkylase (CYP1A2), tolbutamide 4-hydroxylase (CYP2C9) or testosterone 6 beta-hydroxylase (CYP3A4) activities at concentrations of up to 1 mM. It is concluded that venlafaxine has a low potential to inhibit the metabolism of substrates for CYP2D6 such as imipramine and desipramine compared with several of the most widely used SSRIs, as well as the metabolism of substrates for several of the other major human hepatic P450s.British Journal of Clinical Pharmacology 07/1997; 43(6):619-26. DOI:10.1046/j.1365-2125.1997.00591.x · 3.69 Impact Factor
Biological Psychiatry 03/1997; 41(3):377-80. DOI:10.1016/S0006-3223(96)00406-4 · 9.47 Impact Factor
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ABSTRACT: P-glycoprotein (PGP) is well known because of its contribution to multiple-drug resistance during anticancer treatment. More recent work indicates that PGP mediates the transcellular transport of many drugs in addition to anticancer compounds. Because of this reason, its potential role in clinically significant drug-drug interactions has just begun to be realized. This article provides an overview of published in vitro, in situ, and in vivo drug-drug interaction results that are related to PGP transport so that the awareness of the scientific community can be heightened. In addition, several recommendations are made to take full advantage of the recently published data.The Journal of Clinical Pharmacology 01/2000; 39(12):1203-11. DOI:10.1177/00912709922012006 · 2.47 Impact Factor