Thiazolidinediones for type 2 diabetesBMJ 2001; 322 doi: https://doi.org/10.1136/bmj.322.7280.235 (Published 27 January 2001) Cite this as: BMJ 2001;322:235
No evidence exists that pioglitazone induces hepatic cytochrome P450 isoform CYP3A4
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EDITOR—In their editorial on thiazolidinediones for type 2 diabetes Krentz et al incorrectly stated: “Pioglitazone induces cytochrome P450 isoform CYP3A4, raising the possibility of drug interactions, such as with oral contraceptives.”1 No supporting documentation was provided for this statement.
Ishida et al recently evaluated the relation between the therapeutic effects of troglitazone and pioglitazone in steroid induced diabetes.2 Urinary excretion of 6β-hydroxycortisol and the ratio of 6β-hydroxycortisol to cortisol were measured as a marker of CYP3A4 induction. Urinary excretion of 6β-hydroxycortisol was significantly increased with treatment with troglitazone but remained unchanged with treatment with pioglitazone.