Long-term therapy with cyclosporin A does not influence serum concentrations of vitamin D metabolites in patients with multiple sclerosis.

Animal studies have shown that cyclosporin A (CyA) stimulates renal 25-hydroxyvitamin D3 [25(OH)D3]-1 alpha-hydroxylase activity; in contrast, studies in renal transplant recipients indirectly suggest that CyA reduces 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] production. To clarify the effect of CyA on vitamin D metabolite concentrations, we measured parameters of calcium metabolism in 37 CyA-treated patients (median trough whole blood levels 171-222 ng/ml) with multiple sclerosis and initially normal kidney function. The patients participated in a randomized double-blind study to assess the efficacy of CyA in multiple sclerosis. An age- and sex-matched control group (n = 39) received azathioprine (Aza). Measurements were made at the end of a 2-year treatment period. The 1,25(OH)2D3 serum concentrations were not significantly different between the two groups, although they were numerically lower in CyA-treated patients [median (range), 28.4 pg/ml (7.8-85.9) vs 41.0 pg/ml (9.2-105.1) in Aza-treated patients]. The 25(OH)D3 levels were comparable in both groups. There was no correlation between the 25(OH)D3 and 1,25(OH)2D3 concentrations. The renal function in both groups was stable in the last 6 months of the study. At the end of the study period, the endogenous creatinine clearance was significantly lower in the CyA-treated group (85 +/- 17 ml/min versus 99 +/- 22 in the Aza-treated group, P less than 0.05). The carboxyterminal parathyroid hormone (C-PTH) was within the normal range in both groups, although CyA-treated patients had significantly higher concentrations (P less than 0.01). The urinary excretion of mineral ions, cations and protein was similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

RCT Entities:   Population Interventions Outcomes