Effect of simultaneous induction and inhibition of CYP3A by St John's wort and ritonavir on CYP3A activity

• Verfasst von: Hafner-Blumenstiel, Verena [VerfasserIn]
• Verfasst von: Jäger, M [VerfasserIn]
• Verfasst von: Matthée, Anne-Kathrin [VerfasserIn]
• Verfasst von: Ding, Reinhard [VerfasserIn]
• Verfasst von: Burhenne, Jürgen [VerfasserIn]
• Verfasst von: Haefeli, Walter E. [VerfasserIn]
• Verfasst von: Mikus, Gerd [VerfasserIn]
• Titel: Effect of simultaneous induction and inhibition of CYP3A by St John's wort and ritonavir on CYP3A activity
• Verf.angabe: V Hafner, M Jäger, A-K Matthée, R Ding, J Burhenne, WE Haefeli and G Mikus
• Jahr: 2010
• Umfang: 6 S.
• Fussnoten: Advance online publication 18 November 2009 ; Gesehen am 15.06.2023
• Titel Quelle: Enthalten in: Clinical pharmacology & therapeutics
• Ort Quelle: Hoboken, NJ : Wiley-Blackwell, 1960
• Jahr Quelle: 2010
• Band/Heft Quelle: 87(2010), 2, Seite 191-196
• ISSN Quelle: 1532-6535
• DOI: doi:10.1038/clpt.2009.206
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1849814074

Abstract

We aimed to assess the effect of coadministration and withdrawal of a potent cytochrome P450 3A (CYP3A) inhibitor (ritonavir) and a potent CYP3A inducer (St John's wort) on CYP3A enzyme activity in an open, fixed-sequence study design. We investigated the pharmacokinetics of midazolam: (i) at baseline, (ii) after a single dose of either St John's wort or ritonavir (each n = 6), (iii) after 14 days of coadministration of ritonavir (300 mg b.i.d.) and St John's wort (300 mg t.i.d.), and (iv) at 2 days after cessation of both St John's wort and ritonavir. Combined administration of inducer and inhibitor resulted in a predominance of enzyme inhibition: coadministration of St John's wort and ritonavir with intravenous administration of midazolam resulted in an increase in the area under the plasma concentration-time curve (AUC)0-8 h of midazolam to 180% of baseline value, whereas with orally administered midazolam, the AUC0-6 h increased to 412% of baseline value (P < 0.05 for each). After cessation of the coadministered drugs, the AUC0-6 h of orally administered midazolam decreased to 6% of the level observed during combined administration, and the AUC0-8 h of intravenously administered midazolam decreased to 33% of the values observed during combined administration (P < 0.001 for each). Induction may be unmasked after the withdrawal of a combination of a potent CYP3A inhibitor and a potent CYP3A inducer, leading to substantial drops in drug exposure of CYP3A substrates. This may require substantial dose adjustments, particularly of orally administered drugs. Clinical Pharmacology & Therapeutics (2010) 87 2, 191-196. doi:10.1038/clpt.2009.206