A considerable number of single and multiple dose studies have shown that if oral
ciclosporin is taken with 150 to 250 mL of
grapefruit juice, the trough and peak
serum levels and the bioavailability of
ciclosporin may be increased. Increases in trough
serum levels range from 23 to 85%.
Intravenous ciclosporin does not appear to be affected.
The increases appear to be variable and this interaction is difficult, if not impossible, to
control. This is because batches of
grapefruit juice vary so much, and also because considerable patient variation occurs with this interaction. The
US manufacturers suggest that patients on
ciclosporin should avoid whole grapefruit, as well as the juice.