RELIEF OF PRURITUS AND DECREASES IN PLASMA HISTAMINE CONCENTRATIONS DURING ERYTHROPOIETIN THERAPY IN PATIENTS WITH UREMIA

Background. The pathophysiologic aspects of pruritus in patients with chronic renal insufficiency are poorly understood, and there is no uni versally effective treatment. The improvement of pruritus in several p atients receiving erythropoietin therapy raised the possibility that e rythropoietin affects uremic pruritus directly. Methods. We undertook a 10-week placebo-controlled, double-blind, crossover study in a group of patients receiving hemodialysis who had severe pruritus, to invest igate the effects of recombinant human erythropoietin on their pruritu s and plasma histamine levels. Twenty patients with uremia, of whom 10 had severe pruritus and 10 did not, received erythropoietin (36 units per kilogram of body weight three times weekly) and placebo in random order, each for five weeks. The severity of pruritus was scored weekl y, and plasma histamine levels were measured at the beginning and end of each five-week period. Results. Eight of the 10 patients with pruri tus had marked reductions in their pruritus scores during erythropoiet in therapy. The mean (+/- SE) pruritus score decreased from 25 +/- 3 t o 6 +/- 1 in these patients. The pruritus returned within one week aft er the discontinuation of therapy. The improvement was not related to the change in hemoglobin level. These eight patients were successfully treated again with low doses of erythropoietin (18 units per kilogram three times weekly), and the effect has persisted for six months. The patients with pruritus had elevated plasma histamine concentrations ( 20.7 +/- 2.7 nmol per liter), as compared with the patients without pr uritus (4.2 +/- 0.6 nmol per liter; P < 0.001) and normal subjects (2. 1 +/- 0.2 nmol per liter; P < 0.001). Therapy with erythropoietin indu ced a decrease in plasma histamine concentrations in both groups of pa tients with uremia, and recurrences of pruritus after the discontinuat ion of erythropoietin were accompanied by increases in plasma histamin e concentrations. Conclusions. Erythropoietin therapy lowers plasma hi stamine concentrations in patients with uremia and can result in marke d improvement of pruritus.