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Expert Opin Drug Metab Toxicol. 2018 Apr;14(4):429-434. doi: 10.1080/17425255.2018.1459565. Epub 2018 Apr 11.

An update on the clinical pharmacokinetics of fexofenadine enantiomers.

Author information

1
a Department of Pharmacy , Akita University Hospital , Akita , Japan.

Abstract

Fexofenadine is administered as a racemic mixture of (R)- and (S)-enantiomers. The plasma concentrations of (R)-fexofenadine in humans are about 1.5-fold higher than those of the (S)-enantiomer. Such differences in the pharmacokinetics between fexofenadine enantiomers are likely to be dependent on stereoselectivity for affinity to drug-transporters. Areas covered: This review focuses on elucidation of differences in clinical pharmacokinetics between fexofenadine enantiomers. Expert opinion: Differences in pharmacokinetics between fexofenadine enantiomers were caused by organic anion transporting polypeptide (OATP) 2B1, with a minor contribution from P-glycoprotein (P-gp). In vitro studies using OATP2B1 cRNA showed that (R)-fexofenadine uptake into oocytes is greater than (S)-enantiomer uptake. P-gp inducers, carbamazepine, and inhibitors such as itraconazole and verapamil show greater effects on the pharmacokinetics of (S)-fexofenadine. Apple juice and grape fruit juice, OATP2B1 inhibitors, significantly decrease the exposure of both fexofenadine enantiomers, particularly the (S)-enantiomer, but do not change the t1/2. Rifampicin significantly increases plasma concentrations of both enantiomers through inhibition of OATP1B3, whereas enantioselectivity of fexofenadine uptake by OATP1B3-expressing cells has not been observed. Combinations of multiple transporters such as OATP2B1 and P-gp facilitate enantioselective disposition of fexofenadine. Drug-transporters appear to be capable of chiral discrimination for transport of drugs with an asymmetric center.

KEYWORDS:

Fexofenadine enantiomer; P-glycoprotein; organic anion transporting polypeptide; pharmacokinetics; stereoselectivity

PMID:
29635947
DOI:
10.1080/17425255.2018.1459565
[Indexed for MEDLINE]

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