Interaction of intravenous methylprednisolone with oral cyclosporin

The plasma cyclosporin values during 17 consecutive rejection episodes in 13 renal allograft recipients have been monitored by high-performance liquid chromatography and radioimmunoassay. In response to anti-rejection therapy with intravenous methylprednisolone, there was a significant increase of greater than 100 ng/ml on only three occasions. We suggest that elevated cyclosporin values during rejection episodes should not be dismissed as the result of steroid therapy and that the original diagnosis must be reviewed.