Contribution of dose and frequency of administration to the therapeutic effect of growth hormone.

Forty two prepubertal children who were growth hormone insufficient were treated for the first time with 12 IU of biosynthetic methionyl growth hormone a week in three subcutaneous regimens for one year after one year of pretreatment observation. Thirteen received 4 IU growth hormone three days a week (group 1), 21 received 2 IU six days a week (group 2), and eight received 1 IU twice daily six days a week (group 3). The mean (SD) changes in height velocity standard deviation score (SDS) were +3.8 (1.7) in group 1, +5.3 (2.6) in group 2, and +5.9 (2.7) in group 3. There was a highly significant relation between the change in height velocity SDS and pretreatment height velocity SDS with a significant difference between the response of subjects receiving less than 15 IU/m2/week or greater than 15 IU/m2/week growth hormone. Age, bone age, height SDS, and height for bone age SDS did not contribute to the prediction of response during the first year of treatment. We recommend that growth hormone should be given in a dose of at least 15 IU/m2/week by equally divided daily subcutaneous injections.