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ABSTRACT: Introduction
Pharmacokinetic outcomes of transporter-mediated drug-drug interactions (TMDDIs) are increasingly being evaluated clinically. The goal of our study was to determine the effects of selective inhibition of multidrug and toxin extrusion protein 1 (MATE1), using famotidine, on the pharmacokinetics and pharmacodynamics of metformin in healthy volunteers.Methods
Volunteers received metformin alone or with famotidine in a crossover design. As a positive control, the longitudinal effects of famotidine on the plasma levels of creatinine (an endogenous substrate of MATE1) were quantified in parallel. Famotidine unbound concentrations in plasma reached 1 µM, thus exceeding the in vitro concentrations that inhibit MATE1 [concentration of drug producing 50 % inhibition (IC50) 0.25 µM]. Based on current regulatory guidance, these concentrations are expected to inhibit MATE1 clinically [i.e. maximum unbound plasma drug concentration (C max,u)/IC50 >0.1].Results
Consistent with MATE1 inhibition, famotidine administration significantly altered creatinine plasma and urine levels in opposing directions (p < 0.005). Interestingly, famotidine increased the estimated bioavailability of metformin [cumulative amount of unchanged drug excreted in urine from time zero to infinity (A e∞)/dose; p < 0.005] without affecting its systemic exposure [area under the plasma concentration-time curve (AUC) or maximum concentration in plasma (C max)] as a result of a counteracting increase in metformin renal clearance. Moreover, metformin-famotidine co-therapy caused a transient effect on oral glucose tolerance tests [area under the glucose plasma concentration-time curve between time zero and 0.5 h (AUCglu,0.5); p < 0.005].Conclusions
These results suggest that famotidine may improve the bioavailability and enhance the renal clearance of metformin.
SUBMITTER: Hibma JE
PROVIDER: S-EPMC4876051 | biostudies-literature | 2016 Jun
REPOSITORIES: biostudies-literature
Hibma Jennifer E JE Zur Arik A AA Castro Richard A RA Wittwer Matthias B MB Keizer Ron J RJ Yee Sook Wah SW Goswami Srijib S Stocker Sophie L SL Zhang Xuexiang X Huang Yong Y Brett Claire M CM Savic Radojka M RM Giacomini Kathleen M KM
Clinical pharmacokinetics 20160601 6
<h4>Introduction</h4>Pharmacokinetic outcomes of transporter-mediated drug-drug interactions (TMDDIs) are increasingly being evaluated clinically. The goal of our study was to determine the effects of selective inhibition of multidrug and toxin extrusion protein 1 (MATE1), using famotidine, on the pharmacokinetics and pharmacodynamics of metformin in healthy volunteers.<h4>Methods</h4>Volunteers received metformin alone or with famotidine in a crossover design. As a positive control, the longitu ...[more]