Optimum method for administration of biosynthetic human growth hormone:

The use of optimum conventional growth hormone administration, using a growth hormone vial combined with an Auto Injector, was compared with a pen injection system using a cartridge of growth hormone. In both methods of administration the concentration of growth hormone was 16 IU/ml. Thirty patients (22 boys, eight girls) who had all previously been treated with growth hormone (4 IU/ml) administered using needles and syringes (without an Auto Injector) were randomised into receiving one of either treatment for three months and then crossed over for a further three months. Fourteen patients (10 boys, four girls) initialiy received KabiVial 16 IU/ml combined with an Auto Injector while 16 patients (12 boys, four girls) were treated with KabiPen 16 IU/ml. Mean age in both groups was 9-6 years. The majority of patients in both groups were treated with a regimen of either 15 or 20 units/m2/week as a daily subcutaneous injection. Of the 30 patients who started in this trial, two who commenced using an Auto Injector refused to change to a pen system and were excluded from further analysis. When scored on a scale of -5 to +5 general convenience when changing from an Auto Injector to the KabiPen decreased from +4-7 to +1-0. When assessed for pain, the Auto Injector group scored +4-7, which decreased to -0-2 (more painful) for the pen. At the end of the trial 23 patients (82%) chose to continue with the KabiVial/Auto Injector combination as they found this less painful and the child did not see the needle or need to insert the needle manually. Five patients (18%) continued with the KabiPen as they considered the device smaller and easier to use. The accuracy of dosing using KabiVial was 100% compared with the range of 88% to 111% using KabiPen as the latter was available only in 0-5 unit increments. No growth hormone was wasted using KabiVial, although a mean of 0-6 units was wasted with every 16 IU cartridge in the KabiPen system. It is concluded that patients should be able to contribute to the choice of growth hormone delivery systems and that newer methods need careful assessment. (Arch Dis Child 1992;67:994-997) Biosynthetic human growth hormone has traditionally been administered using a powdered growth hormone preparation in a vial to which diluent is added before the resulting solution is drawn up into a smaller syringe before injection. This is a relatively inconvenient form of preparation. Kabi Pharmacia have developed a new range of convenience products which are superior in that the growth hormone powder and water are present in the same applicator and are mixed by closing a syringe barrel (fig 1). Administration is by either needles and syringes or as a cartridge in a pen injection system. ' Both of these new formulations of biosynthetic human growth hormone (Genotropin) are prepared in an identical concentration of 16 IU/ml. Previous trials of a pen injection system against conventional application by needles and syringes have been biased because the volume of injection has been unequal when comparing the two systems,'-3 which may be of particular significance when assessing pain. Although a pen injection system may offer a significant improvement in convenience, the patient still has manually to insert the needle subcutaneously. However, pen injection systems have not been evaluated against optimum treatment using an Auto Injector (which uses a 1 ml syringe and needle), a spring loaded device which automatically inserts the needle subcutaneously and delivers the injection. The dose of growth hormone administered should be related to the patient's size.4 Concern has previously been expressed about the dose regimen using a KabiPen injection system as only 05 unit incre'ments are available up to a maximum of only 4-0 units, which severely limits its use in very small children and adolescents respectively, as well as reducing the dosage accuracy.5 We have used KabiVial (16 IU/ml) in combination with an Auto Injector and compared this device to a KabiPen (16 IU/ml) in order to determine which method was preferred by the patients and their parents. In addition we have examined the accuracy of dose administration and the potential wastage of growth hormone between the two systems. Patients and methods Thirty patients were randomly selected from the Growth Clinic at the Hospital for Sick Children, Great Ormond Street, all of whom were being treated with biosynthetic human growth hormone (Genotropin 12 IU, Kabi Pharmacia) which is a vial of growth hormone reconstituted in a solution of 4 IU/mI. The majority of patients had isolated idiopathic growth hormone deficiency (n= 18); the other diagnostic groups were idiopathic multiple The Medical Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH R Stanhope A Albanese L Moyle G Hamill Correspondence to: Dr Stanhope. Accepted 27 March 1992 994 group.bmj.com on October 29, 2017 Published by http://adc.bmj.com/ Downloaded from