Psychological responses to the needle-free Medi-Jector or the multidose Disetronic injection pen in human growth hormone therapy GH Verrips 1 , RA Hirasing 1 , M Fekkes 1 , T Vogels 1 , SP Verloove-Vanhorick 1 and HA Delemarre-Van de Waal 2 TNO Prevention and Health 1 , Leiden; Department of Paediatrics 2 , University Hospital Vrije Universiteit, Amsterdam, The Netherlands Verrips GH, Hirasing RA, Fekkes M, Vogels T, Verloove-Vanhorick SP, Delemarre-Van de Waal HA. Psychological responses to the needle-free Medi-Jector or the multidose Disetronic injection pen in human growth hormone therapy. Acta Pædiatr 1998; 87: 154–8. Stockholm. ISSN 0803–5253 The aim of the study was to test the hypothesis that daily administration of growth hormone using the Medi- Jector results in fewer adverse psychological responses than needle injection with a multidose injection pen. The Medi-Jector is a needle-free injection device that can deliver growth hormone subcutaneously through jet injection. The group studied consisted of 18 children aged 10 y or over who were participating in a study of the bioequivalence and bioequipotence of the administration of growth hormone through jet injection or needle injection. Previously, all subjects had received growth hormone therapy with commer- cially available multidose injection pens. The study was designed as a prospective, randomized, two-period cross-over trial. A questionnaire was used to assess psychological responses such as non-compliance, opinion on ease of preparation, affective responses to administration and local side-effects, as well as overall preference. In addition, the subjects kept a diary during the study. The subjects found the Medi-Jector less offputting ( p  0:01), less painful with respect to both frequency ( p  0:04) and intensity ( p  0:01) and less unpleasant ( p  0:05) than a multidose injection pen with a 28G needle ( p  0:01). No difference in compliance was detected. Most subjects preferred the Medi-Jector for future use ( p  0:05). The mean score on a 1–10 point scale (10 is excellent) was 7.9 (SD 1.4) for the Medi-Jector and 6.8 (SD 2.3) for the multidose injection pen ( p  0:08). The prevalence of visible bruises each day was higher ( p  0:01) with the Medi- Jector (2.5, SD 2.1) than with the multidose injection pen (0.7, SD 1.1), but children showed indifferent affective responses to bruising. Thirteen out of 18 subjects decided to continue therapy with the Medi-Jector ( p  0:06). It is concluded that use of the Medi-Jector in growth hormone therapy tends to lead to fewer adverse psychological responses than a multidose injection pen with 28G needles. Bruising, children, fear, human growth hormone, injection, pain GH Verrips, TNO Prevention and Health, PO Box 2215, 2301 CE Leiden, The Netherlands The treatment of sick children may cause adverse psycho- logical responses in addition to the negative consequences of the illness itself. Traditionally, children with growth hormone deficiency are treated with growth hormone (GH). This is administered subcutaneously on a daily basis by the children themselves, or by their parents, using an injection pen. This can be an annoying and painful procedure, resulting in non-compliance. There have also been reports of negative effects on child–parent relation- ships as a result of pain, fear and aversion to needles (1, 2). Recently, the Medi-Jector was introduced in The Nether- lands. The Medi-Jector is a needle-free injection device that can deliver GH subcutaneously through jet injection. Needle-free jet injectors have been used for mass immun- ization and insulin administration in diabetics for many years (3). In several studies, jet injectors for the adminis- tration of insulin have been compared with conventional syringes with a needle. The results have been conflicting. Theintz and Sizonenko (1) concluded that the jet injector was rated as less painful. Jovanovic-Peterson et al. (4) found jet-injected insulin more readily accepted by sub- jects than needle injections. Schneider et al. (3) did not report a significant difference in painfulness between jet injectors and syringes with a needle. However, jet injectors have been improved over the last 2 y and newer devices may therefore perform better. In addition, in previous studies, jet injectors were compared to syringes, whereas in the present study a multidose injection pen was used for comparison. The aim of the present study was to test the hypothesis that administration of GH in children using the Medi-Jector results in fewer adverse psychological responses than needle injection with a multidose injection pen. Psychological responses were defined to cover non- compliance, opinion on ease of preparation, affective responses to administration, overall preference and local side-effects. Patients and methods The subjects were 18 children with growth hormone defi- ciency who were participating in a study on the bioequi- valence and bioequipotence of the administration of GH Acta Pædiatr 87: 154–8. 1998  Scandinavian University Press 1998. ISSN 0803-5253