Conditions: Food-drug Interaction
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 18
Healthy volunteers: yes

Brief summary:
Purpose: Grapefruit juice is one of the most extensively studied dietary/natural substances shown to interact with a variety of medications. However, unanswered questions remain regarding the causative ingredients and mechanisms underlying such drug-grapefruit juice interactions. Compounds in grapefruit juice called furanocoumarins have been established as major causative ingredients, which act by inhibiting the elimination (metabolism) of drugs, leading to increased circulating drug concentrations. Increased drug concentrations can in turn lead to increased drug potency or even toxicity. Grapefruit juice also has been shown, paradoxically, to decrease circulating concentrations of some drugs, including the non-sedating antihistamine agent, fexofenadine (Allegra), which undergoes negligible metabolism. Whether or not furanocoumarins mediate the decrease in fexofenadine concentrations is unknown. The purpose of the proposed study is to compare the effects of a "furanocoumarin-free" grapefruit juice with grapefruit juice on circulating concentrations of fexofenadine.

Detailed description:
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.

Arms:
arm 1: This randomized, open-label, single-dose, 3-way crossover study in healthy volunteers will be conducted in the CTRC. Once subjects are identified as eligible to participate, based on their screening evaluation and according to inclusion/exclusion criteria, they will undergo 3 phases. By randomized crossover design, the subject will receive fexofenadine with water, grapefruit juice (GFJ), or furanocoumarin (FC)-free grapefruit juice. arm 2: This randomized, open-label, single-dose, 3-way crossover study in healthy volunteers will be conducted in the CTRC. Once subjects are identified as eligible to participate, based on their screening evaluation and according to inclusion/exclusion criteria, they will undergo 3 phases. By randomized crossover design, the subject will receive fexofenadine with water, grapefruit juice (GFJ), or furanocoumarin (FC)-free grapefruit juice. arm 3: This randomized, open-label, single-dose, 3-way crossover study in healthy volunteers will be conducted in the CTRC. Once subjects are identified as eligible to participate, based on their screening evaluation and according to inclusion/exclusion criteria, they will undergo 3 phases. By randomized crossover design, the subject will receive fexofenadine with water, grapefruit juice (GFJ), or furanocoumarin (FC)-free grapefruit juice. arm 4: This randomized, open-label, single-dose, 3-way crossover study in healthy volunteers will be conducted in the CTRC. Once subjects are identified as eligible to participate, based on their screening evaluation and according to inclusion/exclusion criteria, they will undergo 3 phases. By randomized crossover design, the subject will receive fexofenadine with water, grapefruit juice (GFJ), or furanocoumarin (FC)-free grapefruit juice. arm 5: This randomized, open-label, single-dose, 3-way crossover study in healthy volunteers will be conducted in the CTRC. Once subjects are identified as eligible to participate, based on their screening evaluation and according to inclusion/exclusion criteria, they will undergo 3 phases. By randomized crossover design, the subject will receive fexofenadine with water, grapefruit juice (GFJ), or furanocoumarin (FC)-free grapefruit juice. arm 6: This randomized, open-label, single-dose, 3-way crossover study in healthy volunteers will be conducted in the CTRC. Once subjects are identified as eligible to participate, based on their screening evaluation and according to inclusion/exclusion criteria, they will undergo 3 phases. By randomized crossover design, the subject will receive fexofenadine with water, grapefruit juice (GFJ), or furanocoumarin (FC)-free grapefruit juice.

Interventions: intervention 1: Fexofenadine
Intervention descriptions: intervention 1: This randomized, open-label, single-dose, 3-way crossover study in healthy volunteers will be conducted in the CTRC. Once subjects are identified as eligible to participate, based on their screening evaluation and according to inclusion/exclusion criteria, they will undergo 3 phases. By randomized crossover design, the subject will receive fexofenadine with water, grapefruit juice, or furanocoumarin-free grapefruit juice.

Protocol document: