Systemic and Renal Effects of Nifedipine in Cyclosporine-Associated Hypertension

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Cyclosporine induces hypertension and widespread vasoconstriction after transplantation in addition to reducing kidney function. We studied hemodynamic, renal, and hormonal effects of monotherapy with nifedipine XL (n=37) in liver transplant recipients within a year after transplant (median, 4.4 months). Systemic hemodynamics were determined with thoracic electrical bioimpedance. Blood pressure before therapy was 172±4/108±2 mm Hg. Sixty-four percent of recipients achieved blood pressures less than 140/90 mm Hg mediated by a fall in systemic vascular resistance index (2427±245 dyne · s · cm−5 · m−2 in responders versus 2905 ±281 in nonresponders, P<.01). Despite the fall in systemic vascular resistance, glomerular filtration rates were not changed during nifedipine therapy, as measured by both creatinine and iothalamate clearances. Urinary prostacyclin (6-ketoprostaglandin F1α) was suppressed below normal from 2468±323 ng/d before transplant to 1103±99 ng/d (P<.01) after transplant and did not change during nifedipine therapy. Urinary thromboxane B2 and plasma renin activity also fell after transplant and remained low during nifedipine. These data demonstrate that nifedipine can reverse systemic vasoconstriction associated with hypertension after transplantation. Systemic effects were not transmitted to the kidney sufficiently to improve glomerular filtration rate or reverse hormonal changes within the kidney. Hence, vascular and functional regulation of the kidney was dissociated from the systemic circulation during nifedipine administration after transplantation.

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