title: Increased injection pain with darbepoetin-alpha compared to epoetin-beta in paediatric dialysis patients.
abstract: BACKGROUND
  Darbepoetin-alpha is applicable at longer injection intervals. Our early experience in children on peritoneal dialysis suggested increased injection pain compared to epoetin-beta, possibly due to technical differences or patient anxiety.
  
  
  METHODS
  To verify a possible difference in the painfulness of the injected fluids per se, we performed a prospective, randomized, double-blind trial in 13 paediatric end-stage renal disease patients. They received three injections of equivalent doses of darbepoetin-alpha or epoetin-beta in 0.6 ml saline, using neutral syringes and 27G needles, at 4 week intervals. Pain perception was recorded immediately and after 30 min on a visual analogue scale (VAS, 0 = no pain, 10 = maximal pain; complemented by 5 faces for young children).
  
  
  RESULTS
  The patients perceived more intense immediate injection pain with darbepoetin-alpha than with epoetin-beta (5.4 +/- 1 vs 2.3 +/- 0.6, P < 0.05). This was confirmed by the impression of the parents (5.3 +/- 1 vs 2.0 +/- 0.9, P < 0.05) and the nurses (4.4 +/- 1 vs 2.2 +/- 0.6, P < 0.05). General injection pain was inversely related to patient age (R = -0.77, P = 0.001). Six patients perceived no or a mild difference in injection pain, whereas 7 subjects reported a markedly higher pain score (> or =4 VAS points) with darbepoetin-alpha. After 30 min, the injection site was largely painless with both drugs. No significant local reactions occurred with either medication (0.3 +/- 0.1 vs 0.3 +/- 0.1 on a 5-score scale).
  
  
  CONCLUSIONS
  Subcutaneous injections of darbepoetin-alpha are more painful than those of epoetin-beta in the majority of paediatric patients. The observed difference in painfulness is related to the nature of the injected compounds and may limit the subcutaneous applicability of darbepoetin-alpha in children.
authors.affiliation: Division of Paediatric Nephrology, University Hospital for Paediatric and Adolescent Medicine, Im Neuenheimer Feld 153, 69120 Heidelberg, Germany. claus.peter.schmitt@med.uni-heidelberg.de
authors.forename: Claus Peter
authors.initials: CP
authors.lastname: Schmitt
authors.forename: Barbara
authors.initials: B
authors.lastname: Nau
authors.forename: Christiane
authors.initials: C
authors.lastname: Brummer
authors.forename: Joachim
authors.initials: J
authors.lastname: Rosenkranz
authors.forename: Franz
authors.initials: F
authors.lastname: Schaefer
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D000068256:Darbepoetin alfa; D004311:Double-Blind Method; D004921:Erythropoietin / Q000008:administration & dosage* / Q000009:adverse effects / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous / Q000009:adverse effects; D007279:Injections, Subcutaneous / Q000009:adverse effects; D008297:Male; D010146:Pain / Q000209:etiology*; D011446:Prospective Studies; D011994:Recombinant Proteins; D006435:Renal Dialysis; D012720:Severity of Illness Index
chemical_list: D011994:Recombinant Proteins; C103998:epoetin beta; D004921:Erythropoietin; D000068256:Darbepoetin alfa