Cytochrome P4503A does not mediate the interaction between methadone and ritonavir-lopinavir

Plasma concentrations of orally administered methadone are reduced by the human immunodeficiency virus protease inhibitor combination ritonavir and lopinavir, but the mechanism is unknown. Methadone metabolism, clearance, and drug interactions have been attributed to CYP3A4, but this remains controversial. This investigation assessed the effects of acute (2 days) and steady-state (2 weeks) ritonavir-lopinavir on intravenous and oral methadone metabolism and clearance, hepatic and intestinal CYP3A4/5 activity (using the probe substrate intravenous and oral alfentanil), and intestinal transporter activity (using oral fexofenadine) in healthy volunteers. Plasma and urine concentrations of methadone and metabolite enantiomers, and other analytes, were determined by mass spectrometry. Acute and chronic ritonavir-lopinavir reduced plasma methadone enantiomer concentrations in half, with an average 2.6- and 1.5-fold induction of systemic and apparent oral methadone clearances. Induction was attributable to stereoselectively increased hepatic methadone N-demethylation, hepatic extraction, and hepatic clearance, and there was a strong correlation between methadone N-demethylation and clearance. Methadone renal clearance was unchanged. Alfentanil's systemic clearance and hepatic extraction, apparent oral clearance, and intestinal extraction were reduced to 25%, 16%, and 35% of control, indicating strong inhibition of hepatic and intestinal CYP3A activities. Ritonavir-lopinavir (acute > chronic) increased fexofenadine exposure, suggesting intestinal P-glycoprotein inhibition. No correlation was found between methadone clearance and CYP3A activity. Acute and steady-state ritonavir-lopinavir stereoselectively induced methadone N-demethylation and clearance, despite significant inhibition of hepatic and intestinal CYP3A activity. Ritonavir-lopinavir inhibited intestinal transporters activity but had no effect on methadone bioavailability. These results do not support a significant role for CYP3A or ritonavir-lopinavir-inhibitable intestinal transporters in single-dose methadone disposition.

Medienart:

E-Artikel

Erscheinungsjahr:

2013

Erschienen:

2013

Enthalten in:

Zur Gesamtaufnahme - volume:41

Enthalten in:

Drug metabolism and disposition: the biological fate of chemicals - 41(2013), 12 vom: 25. Dez., Seite 2166-74

Sprache:

Englisch

Beteiligte Personen:

Kharasch, Evan D [VerfasserIn]
Stubbert, Kristi [VerfasserIn]

Links:

Volltext

Themen:

2494G1JF75
ATP Binding Cassette Transporter, Subfamily B, Member 1
CYP3A4 protein, human
Cytochrome P-450 CYP3A
EC 1.14.14.1
EC 1.14.14.55
Journal Article
Lopinavir
Methadone
O3J8G9O825
Research Support, N.I.H., Extramural
Ritonavir
UC6VBE7V1Z

Anmerkungen:

Date Completed 24.06.2014

Date Revised 21.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1124/dmd.113.053991

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM231170149