Effects of erythropoietin on blood pressure.

Increased blood pressure (BP) has been the most commonly reported side effect in trials of treatment of the anemia of chronic renal failure with recombinant human erythropoietin (rHuEPO). An increase in BP develops in one third of patients, in most cases necessitating initiation or increase of antihypertensive therapy. Elevated BP is not related to dose of rHuEPO, nor to the final hematocrit level achieved or the rate of increase of hematocrit. Increases in BP arise particularly during the first 4 months of therapy, and BP usually stabilizes thereafter. rHuEPO therapy does not appear to affect BP in patients with normal renal function. The mechanism of hypertension related to rHuEPO remains uncertain. An increase in systemic vascular resistance occurs in all patients, whether or not BP increases. This is due largely to increased blood viscosity and reversal of hypoxic vasodilatation, but other factors may also contribute. A lack of adequate reduction in cardiac output distinguishes patients in whom BP increases, and this in turn may be due to abnormal cardiovascular autoregulation in these patients. Acute elevation in BP during rHuEPO therapy occasionally results in hypertensive encephalopathy and seizures. This complication is unrelated to the extent or rate of increase in hematocrit, but is associated with a rapid increase in BP, and may occur in previously normotensive patients. Hypertension developing during rHuEPO therapy should be controlled by conventional antihypertensive therapy. If hypertension persists, the rHuEPO dose should be reduced or therapy temporarily discontinued. Frequent BP monitoring during the first 4 months of treatment is mandatory.(ABSTRACT TRUNCATED AT 250 WORDS)