Modulation of abnormalities in renal haemodynamics and vasoactive mediators by nifedipine in patients with psoriasis on low-dose cyclosporin.

Ten patients with psoriasis received a 3-month course of cyclosporin (2.5 mg/kg/day) followed by a 3-month washout period, before commencing a 3-month course of cyclosporin and nifedipine SR 20 mg b.d. Serial haemodynamic and biochemical measurements were performed before, during, and after treatment. Total renal blood flow (RBF) was measured following an intravenous injection of [99mTc]-DTPA based on a renographic analysis of the first-pass effect in the kidneys, and GFR was estimated from the subsequent clearance of this radiotracer. A significant individual change in RBF or GFR was taken as 25% and 20% respectively. Simultaneous assays of the circulating vasoactive mediators renin, aldosterone, angiotensin II, and atrial natriuretic peptide were performed. Two patients withdrew from the study because they could not tolerate nifedipine, leaving eight for complete analysis. The significant reductions in RBF and GFR which occurred on cyclosporin alone (P < 0.05; ANOVA) did not occur with added nifedipine. Four months after this second course, RBF and GFR had recovered. The response to nifedipine was, however, variable and unpredictable. Of the four patients to show a significant decline in GFR on cyclosporin alone, only two showed a significant improvement on the combined therapy. Of the six patients who showed a significant decline in RBF on cyclosporin alone, only four showed benefit from the added nifedipine. Nifedipine suppresses the increase in blood pressure which occurred on cyclosporin alone. The circulating concentration of angiotensin II was significantly less on cyclosporin and nifedipine than on cyclosporin alone (P < 0.05; Student's t test).(ABSTRACT TRUNCATED AT 250 WORDS)