Pain after subcutaneous injection of recombinant human erythropoietin: does Emla cream help?

Recombinant human erythropoietin (rHuEpo) is used to correct anaemia in dialysis patients. Subcutaneous administration of rHuEpo may be associated with pain at the injection site. This study assessed the pain of subcutaneous infiltration of two different preparations of rHuEpo, alpha and beta, and the value of a local anaesthetic (Emla) cream, in reducing the pain of infiltration. Forty-eight haemodialysis patients were enrolled into a double-blind, placebo-controlled, paired-comparison study. Pain was assessed using a visual analogue scale, a verbal descriptive scale and a direct comparison between paired treatments. Subcutaneous injection of rHuEpo alpha was more painful than rHuEpo beta (P < 0.001); using placebo cream 42% of patients described the pain of rHuEpo alpha as severe or very severe, whereas none of the patients found rHuEpo beta so painful. Application of Emla for at least 2 h prior to injection resulted in a significant reduction in the pain of both preparations, but was unable to reduce the pain of rHuEpo alpha to that of rHuEpo beta. Subcutaneous injection of rHuEpo alpha is more painful than rHuEpo beta, even after application of Emla. Although the discomfort of rHuEpo beta is graded as very mild by most adult patients the use of Emla is associated with a significant reduction in discomfort, which may be of benefit to paediatric patients.