Send to:

Choose Destination
See comment in PubMed Commons below
Br J Clin Pharmacol. 2000 Nov;50(5):455-63.

Lack of effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of amlodipine.

Author information

  • 1Clinical Pharmacology Division, Pfizer Central Research, Groton, CT 06340, USA.



To determine whether repeated once daily administration of grapefruit juice altered the pharmacokinetics or pharmacodynamics of the calcium antagonist amlodipine.


S The effects of grapefruit juice on the pharmacokinetics and pharmacodynamics of oral and intravenous amlodipine were assessed in 20 healthy men in a placebo-controlled, open, randomized, four-way crossover study using single doses of amlodipine 10 mg. For 9 days beginning with the day of administration of amlodipine, grapefruit juice (or water control) was given once daily, and blood samples, blood pressure and heart rate measures were obtained. Plasma concentrations of amlodipine and its enantiomers were determined in separate assays by GC-ECD.


Oral amlodipine had high systemic availability (grapefruit juice: 88%; water: 81%). Pharmacokinetic parameters of racemic amlodipine (AUC, Cmax, tmax, and kel) were not markedly changed with grapefruit juice coadministration. Total plasma clearance and volume of distribution, calculated after intravenous amlodipine, were essentially unchanged by grapefruit juice (CL 6.65 ml min-1 kg-1, juice vs 6.93 ml min-1 kg-1, water; Vdss 22.7 l kg-1, juice vs 21.0 l kg-1, water). Grapefruit juice coadministration did not greatly alter the stereoselectivity in amlodipine oral or intravenous kinetics. The sum of S(-) and R(+) enantiomer concentrations correlated well with total racemic amlodipine concentration (r2 = 0. 957; P = 0.0001). Coadministration of grapefruit juice with either route of amlodipine administration did not significantly alter blood pressure changes vs control.


Grapefruit juice has no appreciable effect on amlodipine pharmacodynamics or pharmacokinetics, including its stereoselective kinetics. Bioavailability enhancement by grapefruit juice, noted with other dihydropyridine calcium antagonists, does not occur with amlodipine. Once daily grapefruit juice administration with usual oral doses of amlodipine is unlikely to alter the profile of response in clinical practice.

Comment in

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Blackwell Publishing Icon for PubMed Central
    Loading ...
    Write to the Help Desk