Confirmation of the interaction between cyclosporine and the calcium channel blocker nicardipine in renal transplant patients.

We report seven cases out of eight reversible raises (350% of mean increase) of cyclosporine (CsA) plasma levels in patients receiving the new calcium channel blocker nicardipine (Loxen-Sandoz) and CsA after renal transplantation. Nicardipine was introduced 3 to 36 weeks post transplantation in 7 cases of hypertension and 1 case of angina pectoris. CsA plasma levels raised considerably 1 to 30 days after nicardipine introduction and returned to pretreatment levels 1 to 7 days after withdrawal. Serum creatinine increased in 1/8 patients. These data suggest that nicardipine interferes with CsA metabolism and this interaction is reversible after nicardipine discontinuation. These findings point out the fact that at least some calcium channel blockers need to be cautiously used in patients receiving CsA.