Interaction between cyclosporine and grapefruit juice requires long-term ingestion in stable renal transplant recipients.

STUDY OBJECTIVE

To examine the effect of the concurrent administration of increasing amounts of grapefruit juice, an inhibitor of drug metabolism, on the steady-state pharmacokinetics of cyclosporine.

DESIGN

Open-label, three-period crossover, food-drug interaction study in stable renal transplant patients.

SETTING

A university-affiliated clinical research center.

PATIENTS

Sixteen stable renal transplant recipients.

INTERVENTION

Cyclosporine was administered with 240 ml of water, 240 ml of grapefruit juice, or several 240-ml glasses of grapefruit juice, and serial blood samples were taken to estimate the effect of grapefruit juice on cyclosporine pharmacokinetics.

MEASUREMENTS AND MAIN RESULTS

Grapefruit juice caused a significant increase in cyclosporine area under the curve, however, no significant effect was seen in other pharmacokinetic parameters. Grapefruit juice caused an increase in the 24-hour trough cyclosporine concentration, which may be of clinical significance if long-term ingestion of grapefruit juice is recommended.

CONCLUSION

A drug interaction exists between cyclosporine and grapefruit juice, and it is likely at the level of intestinal drug absorption.