Effect of the CYP3A inhibitor ketoconazole on the PXR-mediated induction of CYP3A activity.

Purpose: The aim of this clinical study was to investigate a previously proposed mechanism of ketoconazole-mediated inhibition of cytochrome P450 3A (CYP3A) induction.

Methods: A two-phase, randomized, cross-over, open, mono-centre trial was carried out. Participants received ketoconazole and St John's wort for 8 days to study the proposed suppression of St John's wort-mediated induction of CYP3A at the transcriptional level.

[Herbal drug-drug interaction and adverse drug reactions].

Herbal medicines are used by many patients. Their known or potential adverse events should be taken into account during treatment with herbal medicines. In this article adverse effects of commonly used herbs are presented.