Drug Metabolism Letters

Zhiyang Zhao
Amgen
Cambridge, MA
USA

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Loxapine P-glycoprotein Interactions In Vitro

Author(s): Andrea Reed, Keith Huie, Elke S. Perloff, James V. Cassella, Lori H. Takahashi.

Abstract:

The antipsychotic drugs risperidone, paliperidone, olanzapine, quetiapine, aripiprazole, clozapine, haloperidol, and chlorpromazine have been reported to have various degrees of interaction (substrate or inhibitor) with the multidrug resistance transporter, P-glycoprotein (P-gp). An interaction of the antipsychotic drug loxapine with P-gp was recently reported, but an IC50 value was not determined. Loxapine (as the succinate salt) was evaluated as a P-gp substrate, and inhibitor of P-gp mediated transport of digoxin in vitro in Caco-2 cells. Loxapine was not a substrate for P-gp but did exhibit weak-to-moderate inhibition (IC50 = 9.1 μM). Since the typical steady state maximal plasma concentrations of loxapine in clinical use have been reported to be in the nanomolar range, pharmacokinetic interactions due to the inhibition of P-gp activity are not expected.

Keywords: Loxapine, P-glycoprotein, Interactions, Antipsychotic drugs, P-gp activity, BCS, ABCB1, blood-brain barrier, Psychotropic drug, In vitro

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Article Details

VOLUME: 6
ISSUE: 1
Year: 2012
Page: [26 - 32]
Pages: 7
DOI: 10.2174/187231212800229255