Experience of pain after subcutaneous administration of different preparations of recombinant human erythropoietin: a randomized, double-blind crossover study.

Subcutaneous erythropoietin (SCEPO) is considered to be more effective than intravenously administered erythropoietin. Patient compliance with SC injections will be important in long-term therapy as there have been reports of pain associated with SCEPO. A double-blind randomized study was performed upon 18 ESRD hemodialysis patients receiving regular subcutaneous erythropoietin replacement therapy for treatment of their anemia. The study involved pain assessment by a visual analogue scale VAS and a verbal descriptive scale VDS following 2 subcutaneous injections of preparation A: rhEPO 2000 IU in 1 ml (Cilag), preparation B: rhEPO 2000 IU in 1 ml (Boehringer Mannheim) and 0.9% saline 1 ml (placebo) over a two-week period. The injections were all administered by the same person and replaced the normal EPO injections for the patient during the study period. Results by VAS and VDS based upon 107 responses showed that preparation A was significantly more painful than preparation B (p less than 0.001) or saline (p less than 0.01). An unexpected finding was that preparation B was less painful than the placebo for VAS (p less than 0.05). It seems unlikely that the erythropoietin itself was responsible for the difference. Further work will be necessary to determine the pain causing factor in preparation A, and the possible local anaesthetic factor in preparation B.