SEROSTIM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SEROSTIM (SEROSTIM).
SEROSTIM is a recombinant human growth hormone that binds to growth hormone receptors, activating JAK2/STAT5 signaling pathways, leading to increased production of insulin-like growth factor 1 (IGF-1). It promotes linear growth, protein synthesis, and lipolysis.
| Metabolism | Metabolized primarily in the liver and kidneys via proteolytic degradation; no significant involvement of CYP450 enzymes. |
| Excretion | Primarily renal (90% metabolized in liver and kidneys; 0.1% excreted unchanged in urine); biliary/fecal negligible. |
| Half-life | Terminal half-life of approximately 2-3 hours after subcutaneous administration; prolonged in renal impairment (up to 6-8 hours). |
| Protein binding | Approximately 30-40% bound to growth hormone-binding protein (GHBP) in plasma. |
| Volume of Distribution | Vd of approximately 0.07 L/kg in adults; higher in children (~0.1 L/kg); reflects distribution into extracellular fluid and well-perfused tissues. |
| Bioavailability | Subcutaneous: 75-85% (compared to intravenous); intramuscular: approximately 60% (not recommended for Serostim). |
| Onset of Action | Subcutaneous: peak serum concentration at 2-4 hours; clinical effect on growth and metabolism begins within days to weeks. |
| Duration of Action | Duration of metabolic effects (e.g., IGF-1 elevation) persists for 12-24 hours after subcutaneous dose; requires daily administration for growth promotion. |
0.1 mg/kg subcutaneously once daily for 4 weeks; alternatively, 4 mg subcutaneously once daily for 4 weeks for patients ≥35 kg.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for GFR ≥15 mL/min; insufficient data for GFR <15 mL/min. |
| Liver impairment | No specific dose adjustment for Child-Pugh A, B, or C; use with caution in severe impairment due to increased GH bioavailability. |
| Pediatric use | 0.1 mg/kg subcutaneously once daily for 4 weeks; maximum dose 4 mg/day. |
| Geriatric use | No specific dose adjustment; start at lowest effective dose due to increased sensitivity and higher risk of adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SEROSTIM (SEROSTIM).
| Breastfeeding | Somatropin is excreted in human breast milk in low amounts. M/P ratio unknown. Caution is advised; consider developmental and health benefits of breastfeeding along with mother's need for the drug. Monitor infant for signs of growth hormone effects. |
| Teratogenic Risk | SEROSTIM (somatropin) is not recommended during pregnancy due to limited data. Animal studies have shown no evidence of teratogenicity, but no adequate human studies exist. Risk in first trimester is unknown; growth hormone may cross the placenta minimally. The drug may affect fetal growth if used in second and third trimesters; use only if clearly needed and maternal benefit outweighs potential risk. |
■ FDA Black Box Warning
Increased risk of mortality in pediatric patients with Prader-Willi syndrome who are severely obese or have severe respiratory impairment. Use is contraindicated in these patients.
| Serious Effects |
["Acute critical illness (e.g., open heart surgery, abdominal surgery, multiple accidental trauma, or respiratory failure) due to increased mortality","Children with PWS who are severely obese or have severe respiratory impairment","Active malignancy","Diabetic retinopathy","Hypersensitivity to somatropin or any excipients"]
| Precautions | ["Increased risk of malignancies","Slipped capital femoral epiphysis in children","Intracranial hypertension (pseudotumor cerebri)","Fluid retention and edema","Hypersensitivity reactions","Pancreatitis","Glucose intolerance and diabetes mellitus","Scoliosis progression in PWS patients"] |
Loading safety data…
| Fetal Monitoring | Monitor maternal IGF-1 levels, blood glucose, and thyroid function periodically. In pregnancy, watch for gestational diabetes, fetal growth via ultrasound, and signs of macro-or microsomia. Monitor for maternal edema, hypertension, and carpal tunnel syndrome. |
| Fertility Effects | Growth hormone may restore fertility in women with growth hormone deficiency by improving ovarian function. In normal women, high doses may disrupt menstrual cycles. No known adverse effects on fertility for either sex, but data are limited. |