Weight-independent dosing of cyclosporine--an alternative to the "mg/kg" doctrine.

Cyclosporine is usually prescribed as "mg CsA per kg body weight", and blood levels are used for guiding CsA therapy. The present study evaluated whether it is sensible to dose in "mg/kg" if one wishes to obtain specific CsA blood levels. In a retrospective analysis, 1071 consecutive CsA whole-blood trough levels from 164 renal transplant patients, measured by monoclonal parent RIA, were correlated with the respective oral CsA doses and several demographic parameters, including gender, age, weight, height, and time after transplantation. From this, we derived a concept of "weight-independent CsA dosing" which was prospectively tested in three series of patients during the first days after renal transplantation: 58 patients received 2x 100 mg/day CsA from day 0 with the intention to reach target levels of 40-80 ng/ml, 42 patients received 2x 200 mg/day CsA from day 4 (target: 100-200 ng/ml), and 38 patients received 2x 300 mg/day from day 4 (target: 100-200 ng/ml). In the retrospective analysis, the individual, patient-specific relation of CsA level to CsA dose (in mg) was found to depend only on height (P = 0.02) and time after transplantation (P < 0.001), but not on body weight (b. wt.). If the CsA dose was expressed in "mg/kg", patients < or = 55 kg b. wt. required nearly twice the doses of patients > or = 75 kg b. wt., whereas the mean CsA requirement was the same when expressed in "mg".(ABSTRACT TRUNCATED AT 250 WORDS)