Do Furanocoumarins Mediate the Fexofenadine-grapefruit Juice Interaction?

Participants: Healthy volunteers of any race/ethnicity, ranging in age from 18 to 65 years, will be enrolled.

Procedures (methods): Procedures will include administration of water, furanocoumarin-free grapefruit juice, or grapefruit juice with fexofenadine; placement of an intravenous (IV) line; and collection of blood over 72 hours.

Inclusion criteria

• Men or women between the ages of 18 and 65
• Normal screening laboratory test results
• Able to understand the informed consent form
• Willing to abstain from grapefruit products and all fruit juices for one week prior to and during the study
• Willing to abstain from alcohol and caffeinated beverages the evening prior to each study day

Exclusion criteria

• History of intolerance to grapefruit products
• History of any allergy or hypersensitivity to grapefruit products or fexofenadine
• History of significant medical conditions that the study physician believes would increase risk
• History of significant alcohol abuse and/or illicit drug use
• Tobacco use within the month preceding the study
• Pregnancy or breast-feeding
• Taking concomitant medications, both prescription and non-prescription (including herbal products), known to alter fexofenadine blood levels or P-gp and/or OATP activity (women stabilized on hormonal methods of birth control will be allowed to participate)