home > drugs a-z list > tev-tropin (somatropin, rdna origin, for injection) drug center > tev-tropin (somatropin, rdna origin, for injection) drug - clinical pharmacology

Clinical trials have demonstrated that TEV-TROPIN® is equivalent in its therapeutic effectiveness and in its pharmacokinetic profile to those of human growth hormone of pituitary origin (somatropin). TEV-TROPIN® stimulates linear growth in children who lack adequate levels of endogenous growth hormone. Treatment of growth hormone-deficient children with TEV-TROPIN® produces increased growth rates and IGF-1 (Insulin-Like Growth Factor-1) concentrations that are similar to those seen after therapy with human growth hormone of pituitary origin.

Both TEV-TROPIN® and somatropin have also been shown to have other actions including:

Tissue Growth

1. Skeletal Growth. TEV-TROPIN® stimulates skeletal growth in patients with growth hormone deficiency. The measurable increase in body length after administration of TEV-TROPIN® results from its effect on the epiphyseal growth plates of long bones. Concentration of IGF-1, which may play a role in skeletal growth, are low in the serum of growth hormone-deficient children but increase during treatment with TEV-TROPIN®. Mean serum alkaline phosphatase concentrations are increased.
2. Cell Growth. It has been shown that there are fewer skeletal muscle cells in short statured children who lack endogenous growth hormone as compared with normal children. Treatment with somatropin results in an increase in both the number and size of muscle cells.
3. Organ Growth. Somatropin influences the size of internal organs and it also increases red cell mass.

Protein Metabolism

Linear growth is facilitated, in part, by increased cellular protein synthesis. Nitrogen retention, as demonstrated by decreased urinary nitrogen excretion and serum urea nitrogen, results from treatment with somatropin.

Carbohydrate Metabolism

Children with hypopituitarism sometimes experience fasting hypoglycemia that is improved by treatment with somatropin. Large doses of somatropin may impair glucose tolerance.

Lipid Metabolism

Administration of somatropin to growth hormone-deficient patients mobilizes lipid, reduces body fat stores, and increases plasma fatty acids.

Mineral Metabolism

Sodium, potassium, and phosphorous are conserved by somatropin. Serum concentrations of inorganic phosphates increased in patients with growth hormone deficiency after therapy with TEV-TROPIN or somatropin. Serum calcium concentrations are not significantly altered in patients treated with either somatropin or TEV-TROPIN®.

Connective Tissue Metabolism

Somatropin stimulates the synthesis of chondroitin sulfate and collagen as well as the urinary excretion of hydroxyproline.

Pharmacokinetics

Following intravenous administration of 0.1 mg/kg of TEV-TROPIN®, the elimination half-life was about 0.42 hours (approximately 25 minutes) and the mean plasma clearance (±SD) was 133 (±16) mL/min in healthy male volunteers.

In the same volunteers, after a subcutaneous injection of 0.1 mg/kg TEV-TROPIN to the forearm, the mean peak serum concentration (±SD) was 80 (±50) ng/mL which occurred approximately 7 hours post-injection and the apparent elimination half-life was approximately 2.7 hours. Compared to intravenous administration, the extent of systemic availability from subcutaneous administration was approximately 70%.

Last reviewed on RxList: 8/29/2011
This monograph has been modified to include the generic and brand name in many instances.