Long term effects of ACE inhibitors on the erythrocytosis in renal transplant recipients.

Erythrocytosis is infrequently seen in renal transplant recipients. Both theophylline and angiotensin converting enzyme (ACE) inhibitors have been reported to decrease the elevated hematocrit (Hct) and hemoglobin (Hgb) levels. We studied the efficacy of the ACE inhibitors ramipril (n = 6) and enalapril (n = 1) in seven stable renal transplant recipients. Although the ACE inhibitors significantly reduced the elevated Hct and Hgb levels during the short and long term (Hct 53 +/- 1 vs 48.8 +/- 0.7%; Hgb 17.8 +/- 0.4 vs 16.7 +/- 0.3 vs 16.7 +/- 0.3 gm/dl, at 1 year), the clinical significance of these reductions remains unknown. During therapy there were no significant changes in the blood pressure, serum creatinine and potassium levels and the medications were well tolerated.