A comparison of subcutaneous and intramuscular administration of human growth hormone in the therapy of growth hormone deficiency.

The sc and im administration of human GH (hGH) was compared in the therapy of GH deficiency. The peak and integrated concentrations of hGH in the plasma of the patients were similar after sc and im injection of an initial dose (0.1 U/kg) of hGH. The peak hGH concentration occurred at 2 h in both groups. The posttreatment height velocity and the change in height velocity at 3-month intervals were also similar in the im and sc groups. The somatomedin generation test resulted in a higher mean peak of somatomedin C after sc injection; however, if the individual peaks of somatomedin C were averaged, there was no difference between sc and im injection. A cross-over at 9 months of therapy to determine patient acceptance of im vs. sc injections indicated overwhelming acceptance of the sc route. The antibody responses to hGH were similar in both groups. We conclude that sc injection of hGH is an effective and safe mode of therapy for GH deficiency. The lipoatrophy that occurred infrequently at the injection site can be eliminated by rotation of sites. Subcutaneous administration of hGH will be more acceptable by the patients with less pain and less noncompliance.