Time‐dependent inhibition (TDI) of CYP3A4 and CYP2C9 by noscapine potentially explains clinical noscapine–warfarin interaction

Abstract

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Clinical cases reported to the Swedish adverse drug interactions register (SWEDIS) indicated that drug-drug interaction (DDI) existed when warfarin was co-administered with noscapine.• In vitro testing with recombinant human enzyme showed that noscapine inhibited CYP3A4 and CYP2C9 with an IC50 of around 1 mM.• However, the clinical relevance of these in vitro data remains to be explored. WHAT THIS STUDY ADDS• Noscapine was demonstrated to be both a reversible inhibitor and a time-dependent inhibitor to CYP3A4 and CYP2C9.• DDI magnitude predicted from reversible inhibition and time-dependent inhibition (TDI) kinetic parameters showed that the TDI might be a noteworthy factor resulting in clinical noscapine-warfarin interaction. AIMSTo investigate the inhibition potential and kinetic information of noscapine to seven CYP isoforms and extrapolate in vivo noscapine-warfarin interaction magnitude from in vitro data. METHODSThe activities of seven CYP isoforms (CYP3A4, CYP1A2, CYP2A6, CYP2E1, CYP2D6, CYP2C9, CYP2C8) in human liver microsomes were investigated following co-or preincubation with noscapine. A two-step incubation method was used to examine in vitro time-dependent inhibition (TDI) of noscapine. Reversible and TDI prediction equations were employed to extrapolate in vivo noscapine-warfarin interaction magnitude from in vitro data. RESULTSAmong seven CYP isoforms tested, the activities of CYP3A4 and CYP2C9 were strongly inhibited with an IC50 of 10.8 Ϯ 2.5 mM and 13.3 Ϯ 1.2 mM. Kinetic analysis showed that inhibition of CYP2C9 by noscapine was best fit to a noncompetitive type with Ki value of 8.8 mM, while inhibition of CYP3A4 by noscapine was best fit to a competitive manner with Ki value of 5.2 mM. Noscapine also exhibited TDI to CYP3A4 and CYP2C9. The inactivation parameters (KI and kinact) were calculated to be 9.3 mM and 0.06 min -1 for CYP3A4 and 8.9 mM and 0.014 min -1 for CYP2C9, respectively. The AUC of (S)-warfarin and (R)-warfarin was predicted to increase 1.5% and 1.1% using Cmax or 0.5% and 0.4% using unbound Cmax with reversible inhibition prediction equation, while the AUC of (S)-warfarin and (R)-warfarin was estimated to increase by 110.9% and 48.9% using Cmax or 41.8% and 32.7% using unbound Cmax with TDI prediction equation. CONCLUSIONSTDI of CYP3A4 and CYP2C9 by noscapine potentially explains clinical noscapine-warfarin interaction.

Characterization of Inhibition Kinetics of (S)-Warfarin Hydroxylation by Noscapine: Implications in Warfarin Therapy

“…3). Interestingly, when diclofenac 49-hydroxylation was used as the probe reaction, noscapine inhibited CYP2C9 activity in a noncompetitive manner in pooled HLMs (Fang et al, 2010). Similar substrate-dependent differences in inhibitory mechanism were previously reported for CYP3A4 inhibitors.…”

“…Previously, noscapine was shown to inhibit diclofenac 49-hydroxylation via a mechanism of time-dependent inhibition (Fang et al, 2010). To examine whether noscapine inhibits warfarin metabolism by a similar mechanism, noscapine at different concentrations was incubated with pooled HLMs for different time periods, and the residual CYP2C9 activity was determined using (S)-warfarin as the probe drug.…”

“…1) has a 5-fold higher anticoagulant activity than the (R)-isomer (Hirsh et al, 2001), and is primarily metabolized by CYP2C9 (Rettie et al, 1992). A previous study demonstrated that noscapine inhibited CYP2C9 turnover in a noncompetitive and time-dependent manner in human liver microsomes (HLMs) when diclofenac was used as the probe substrate (Fang et al, 2010). Of note, CYP2C9 inhibitors have shown substrate-dependent differences in inhibitory potencies, with warfarin generally being more susceptible to CYP2C9 inhibition.…”

Substrate-dependent modulation of the catalytic activity of CYP3A by erlotinib

“…The concentrations of positive control inhibitors used are as follows [21,24,25] : 1 μmol/L ketoconazole for CYP3A, 10 μmol/L furafylline for CYP1A2, 10 μmol/L sulfaphenazole for CYP2C9, 5 μmol/L montelukast for CYP2C8, 2.5 μmol/L 8-methoxypsoralen for CYP2A6, 10 μmol/L quinidine for CYP2D6 and 50 μmol/L clomethiazole for CYP2E1. For CYP isoforms that were strongly inhibited, the concentrations at which the enzymes were 50% inhibited (IC 50 values) were determined using various concentrations of erlotinib for CYP3A and for CYP2C8.…”

Time-Dependent Inhibition of CYP2C19 by Isoquinoline Alkaloids: In Vitro and In Silico Analysis

“…For example, noscapine (19), a phthalideisoquinoline alkaloid isolated from opium and widely used as an antitussive drug, has been associated with serious drug interactions when coadministered with warfarin (Ohlsson et al, 2008;Scordo et al, 2008;Fang et al, 2010). It has been demonstrated to inhibit CYP2C9 and CYP3A4 in vitro in a time-dependent fashion (Fang et al, 2010).…”