Format

Send to

Choose Destination
See comment in PubMed Commons below
Drug Metab Dispos. 2008 Jan;36(1):73-80. Epub 2007 Oct 3.

Trimethoprim and the CYP2C8*3 allele have opposite effects on the pharmacokinetics of pioglitazone.

Author information

1
Department of Clinical Pharmacology, University of Helsinki, Helsinki University Central Hospital, Helsinki, Finland.

Abstract

We studied the effects of the CYP2C8 inhibitor trimethoprim and CYP2C8 genotype on the pharmacokinetics of the antidiabetic pioglitazone. In a randomized crossover study, 16 healthy volunteers with the CYP2C8(*)1/(*)1 (n = 8), (*)1/(*)3 (n = 5), or (*)3/(*)3 (n = 3) genotype ingested 160 mg of trimethoprim or placebo twice daily for 6 days. On day 3, they ingested 15 mg of pioglitazone. The effects of trimethoprim on pioglitazone were characterized in vitro. Trimethoprim raised the area under the plasma pioglitazone concentration-time curve (AUC(0-infinity)) by 42% (p < 0.001) and decreased the formation rates of pioglitazone metabolites M-IV and M-III (p < 0.001). During the placebo phase, the weight-adjusted AUC(0-infinity) of pioglitazone was 34% smaller in the CYP2C8(*)3/(*)3 group and 26% smaller in the CYP2C8(*)1/(*)3 group than in the CYP2C8(*)1/(*)1 group (p < 0.05). Trimethoprim inhibited M-IV formation in vitro (inhibition constant 38.2 muM), predicting the in vivo interaction. In conclusion, drug interactions and pharmacogenetics affecting the CYP2C8 enzyme may change the safety of pioglitazone.

PMID:
17913794
DOI:
10.1124/dmd.107.018010
[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center