INTERACTIONS OF GRAPEFRUIT WITH MEDICATIONS

Grapefruit Juice and Immunosuppressant Drugs

Grapefruit juice was found to interact with cyclosporine, a popular transplant medication. The serum concentration of cyclosporine was found to increase when grapefruit juice was coadministered with the drug. In fact, some transplant physicians are reported to use grapefruit juice to increase the bio-availablity of cyclosporine. (Many experts discourage such practice as it is difficult to control the concentration this way.)

In 12 kidney transplant patients receiving cyclosporine (Sandimmune, Neoral) and grapefruit juice, the ratio of metabolite AUC to cyclosporine AUC and peak concentrations were increased while trough levels were not significantly changed.

Fourteen healthy subjects, experienced a 45% increase in AUC and increased maximal plasma concentrations when cyclosporine was given with grapefruit juice.

Another study looked at 11 renal transplant patients receiving their usual dosage of cylcosporine (Sandimmune) for one week with either water or single-strength grapefruit juice. Trough cyclosporine concentrations were measured. 

In 8 patients, trough cyclosporine levels increased, for an average of 32% when cyclosporine was given with grapefruit juice. 

10 patients had their trough cyclosporine levels declined an average decrease of 27% when they resumed taking cyclosporine with water.

Do not to drink grapefruit juice while taking cyclosporine, unless specifically advised to do so by your transplant physician.

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