Grapefruit juice-felodipine interaction: reproducibility and characterization with the extended release drug formulation

Br J Clin Pharmacol. 1995 Aug;40(2):135-40.

Abstract

1. Felodipine 10 mg extended release was administered with 250 ml regular-strength grapefruit juice or water in a randomized crossover manner followed by a second grapefruit juice treatment in 12 healthy men. The pharmacokinetics of felodipine and primary oxidative metabolite, dehydrofelodipine, were evaluated. 2. Initial grapefruit juice treatment increased felodipine AUC (mean +/- s.d.; 56.6 +/- 21.9 vs 28.1 +/- 11.5 ng ml-1 h; P < 0.001) and Cmax (8.1 +/- 2.5 vs 3.3 +/- 1.2 ng ml-1; P < 0.001) compared with water. Felodipine tmax (median; 2.8 vs 3.0 h) and t1/2 (7.3 +/- 3.7 vs 6.9 +/- 3.6 h) were not altered. 3. Readministration of felodipine with grapefruit juice produced mean felodipine AUC (61.5 +/- 32.2 ng ml-1 h) and Cmax (8.4 +/- 4.8 ng ml-1) which were similar to the initial grapefruit juice treatment 1-3 weeks previously. Felodipine AUC (r = 0.73, P < 0.01) and Cmax (r = 0.69, P < 0.02) correlated between grapefruit juice treatments among individuals. 4. The % increase in felodipine AUC with the initial grapefruit juice treatment compared with water correlated with the % increase in felodipine Cmax among individuals (r = 0.80, P < 0.01). Dehydrofelodipine AUC (74.7 +/- 28.7 vs 48.5 +/- 16.3 ng ml-1 h; P < 0.01) and Cmax (12.1 +/- 2.9 vs 7.9 +/- 2.6 ng ml-1; P < 0.01) were augmented with grapefruit juice compared with water.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Beverages
  • Calcium Channel Blockers / pharmacokinetics*
  • Citrus* / chemistry
  • Cross-Over Studies
  • Delayed-Action Preparations
  • European Continental Ancestry Group
  • Felodipine / administration & dosage
  • Felodipine / analogs & derivatives*
  • Felodipine / metabolism
  • Felodipine / pharmacokinetics*
  • Food-Drug Interactions
  • Humans
  • Linear Models
  • Male
  • Reproducibility of Results

Substances

  • Calcium Channel Blockers
  • Delayed-Action Preparations
  • dehydrofelodipine
  • Felodipine