Effects of the moderate CYP3A4 inhibitor, fluconazole, on the pharmacokinetics of fesoterodine in healthy subjects

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Available data suggest that fesoterodine dosage should not exceed 4 mg once daily when taken concomitantly with potent CYP3A4 inhibitors, such as ketoconazole. Currently, no information is available on whether dose adjustment is necessary when fesoterodine...

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Published in:British journal of clinical pharmacology Vol. 72; no. 2; pp. 263 - 269
Main Authors: Malhotra, Bimal, Dickins, Maurice, Alvey, Christine, Jumadilova, Zhanna, Li, Xiaoxi, Duczynski, Gregory, Gandelman, Kuan
Format: Journal Article
Language:English
Published: Oxford, UK Blackwell Publishing Ltd 01.08.2011
Blackwell Science Inc
Subjects:
Adolescent
Adult
Analysis of Variance
Antifungal Agents - pharmacology
Area Under Curve
Benzhydryl Compounds - pharmacokinetics
Cross-Over Studies
Cytochrome P-450 CYP3A - metabolism
Cytochrome P-450 CYP3A Inhibitors
Double-Blind Method
Drug Interactions
drug–drug interactions
Female
fesoterodine
fluconazole
Fluconazole - pharmacology
Half-Life
Humans
Male
Middle Aged
Muscarinic Antagonists - pharmacokinetics
overactive bladder
pharmacokinetics
Uropharmacology Themed Section
Young Adult
ISSN:0306-5251, 1365-2125, 1365-2125
Online Access:Get full text
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Summary:WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Available data suggest that fesoterodine dosage should not exceed 4 mg once daily when taken concomitantly with potent CYP3A4 inhibitors, such as ketoconazole. Currently, no information is available on whether dose adjustment is necessary when fesoterodine is administered with a moderate CYP3A4 inhibitor. WHAT THIS STUDY ADDS • This study shows that adjustment of fesoterodine dose is not warranted when co‐administered with a moderate CYP3A4 inhibitor. AIMS To assess the effects of fluconazole, a moderate CYP3A4 inhibitor, on the pharmacokinetics (PK) and safety/tolerability of fesoterodine. METHODS In this open‐label, randomized, two‐way crossover study, 28 healthy subjects (18–55 years) received single doses of fesoterodine 8 mg alone or with fluconazole 200 mg. PK endpoints, including the area under the plasma concentration–time curve from 0 to infinity (AUC(0,∞)), maximum plasma concentration (Cmax), time to Cmax (tmax), and half‐life (t1/2), were assessed for 5‐hydroxymethyl tolterodine (5‐HMT), the active moiety of fesoterodine. RESULTS Concomitant administration of fesoterodine with fluconazole increased AUC(0,∞) and Cmax of 5‐HMT by approximately 27% and 19%, respectively, with corresponding 90% confidence intervals of (18%, 36%) and (11%, 28%). There was no apparent effect of fluconazole on 5‐HMT tmax or t½. Fesoterodine was generally well tolerated regardless of fluconazole co‐administration, with no reports of death, serious adverse events (AEs) or severe AEs. Following co‐administration of fesoterodine with fluconazole, 13 subjects (48%) experienced a total of 40 AEs; following administration of fesoterodine alone, six subjects (22%) experienced a total of 19 AEs. The majority of AEs were of mild intensity. There were no clinically significant changes in laboratory or physical examination parameters. CONCLUSION Fesoterodine 8 mg single dose was well tolerated when administered alone or with fluconazole. Based on the observed increase in 5‐HMT exposures being within the inherent variability of 5‐HMT pharmacokinetics, adjustment of fesoterodine dose is not warranted when co‐administered with a moderate CYP3A4 inhibitor provided they are not also inhibitors of transporters.
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ISSN:0306-5251
1365-2125
1365-2125
DOI:10.1111/j.1365-2125.2011.04007.x