The Impact of Grapefruit Juice on the Response to Clopidogrel

The Impact of Grapefruit Juice on the Response to a Loading Dose and Maintenance Dose of Clopidogrel in Healthy Volunteers

This study will measure the percentage of platelet aggregation inhibition with a loading dose of clopidogrel (300 mg) using the VerifyNow Assay System in healthy volunteers who have drank 11 oz of grapefruit juice. It will also measure the percentage of platelet aggregation inhibition with a maintenance dose of clopidogrel (75 mg/day) using the VerifyNow Assay System in healthy volunteers who have drank 11 oz grapefruit juice daily.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Dietary supplement: Grapefruit juice; Drug: Clopidogrel 300 mg; Drug: Clopidogrel 75 mg/day

Detailed Description

This study will examine the effect of GFJ on the loading dose (300 mg) of clopidogrel and will evaluate the effect of GFJ on the maintenance dose (75 mg/day) of clopidogrel. Subjects will be randomized to either initially receive GFJ prior to their loading dose of clopidogrel or receive GFJ prior to their second loading dose. The subjects who have been randomized to receive GFJ initially will drink two small cans (11 oz total) of regular strength GFJ in the morning, followed two hours later by a loading dose (300 mg) of clopidogrel and will then return to the clinic 6 hours after their loading dose to have their platelet inhibition measured. Subjects will have ~ 5 milliliters (1 teaspoonful) of whole blood drawn from an antecubital vein in their forearm via a 21 gauge needle attached to a blue-top plastic vacuette sodium citrate blood collection (Greiner, Monroe, NC) tube to test inhibition of platelet aggregation. After their first loading dose, a 2 week washout period will follow to allow for their platelet aggregation to return to normal. Following the washout period, the subjects will take their second loading dose of clopidogrel and again return to the clinic for platelet inhibition measurement. The same timing will be followed for the loading dose taken without prior GFJ.

During the maintenance dose phase of this study, subjects will take 75 mg/day clopidogrel for 7 days with or without GFJ. Subjects will be randomized to either GFJ during the first period or GFJ during the second period. A minimum 2 week washout period will occur between the two 7 day courses of clopidogrel. Platelet inhibition measurement will occur at the end of each 7 day period as described above.

• Study Type: Interventional
• Enrollment (Actual): 32
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Nebraska
    • Omaha, Nebraska, United States, 68131
      • Creighton Cardiac Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 17 years to 38 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Ages 19-40
• Health status confirmed by medical history and physical examination and laboratory analysis

Exclusion Criteria:

• Pregnancy
• Taking routine prescription or over-the-counter prescriptions
• Taken over-the-counter analgesic/anti-inflammatory medication within two weeks of study participation
• Recently had grapefruit juice or regularly drinks grapefruit juice

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Loading Dose; Participants received a 300 mg dose of clopidogrel with or without GFJ.	Dietary supplement: Grapefruit juice; Participants received grapefruit juice during 1 of the 2 periods.; Drug: Clopidogrel 300 mg
Experimental: Maintenance Dose; Participants received clopidogrel 75 mg/day for 7 days with or without GFJ	Dietary supplement: Grapefruit juice; Participants received grapefruit juice during 1 of the 2 periods.; Drug: Clopidogrel 75 mg/day

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
% Platelet Inhibition	% platelet inhibition measured by Verify Now	6 hours

Collaborators and Investigators

• Sponsor: Creighton University
• Investigators: Principal Investigator: Tammy Burns, PharmD, Creighton Cardiac Center

Study record dates

Study Major Dates

• Study Start: November 1, 2008
• Primary Completion (Actual): July 1, 2011
• Study Completion (Actual): July 1, 2011

Study Registration Dates

• First Submitted: January 6, 2009
• First Submitted That Met QC Criteria: January 6, 2009
• First Posted (Estimate): January 7, 2009

Study Record Updates

• Last Update Posted (Estimate): October 1, 2012
• Last Update Submitted That Met QC Criteria: August 28, 2012
• Last Verified: August 1, 2012

More Information

Terms related to this study

• Keywords: Platelet Aggregation Inhibition
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Platelet Aggregation Inhibitors; Purinergic P2Y Receptor Antagonists; Purinergic P2 Receptor Antagonists; Purinergic Antagonists; Purinergic Agents; Clopidogrel
• Other Study ID Numbers: 08-15073