HUMATROPE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HUMATROPE (HUMATROPE).
HUMATROPE (somatropin) is a recombinant human growth hormone that binds to growth hormone receptors on cell surfaces, activating JAK2/STAT signaling pathways, leading to increased IGF-1 production and various anabolic, lipolytic, and anti-insulin effects.
| Metabolism | Primarily metabolized in the liver and kidneys via proteolysis; excreted renally. |
| Excretion | Renal (biliary/fecal negligible). |
| Half-life | Terminal elimination half-life: 3.5–4.5 hours (IV) in adults; longer (6–8 hours) in children; clinical significance: supports daily subcutaneous dosing for growth hormone deficiency. |
| Protein binding | ~80% bound to growth hormone-binding protein (GHBP). |
| Volume of Distribution | 0.07–0.1 L/kg (central compartment); clinical meaning: limited extravascular distribution consistent with a large peptide hormone. |
| Bioavailability | Subcutaneous: ~80% (range 70–90%). |
| Onset of Action | Subcutaneous: IGF-1 elevation detectable within 3–6 hours; clinical effect (growth) after weeks to months. |
| Duration of Action | Subcutaneous: IGF-1 levels remain elevated for 12–18 hours; clinical growth effects require chronic daily administration. |
0.2 mg/kg subcutaneously once daily (maximum 0.3 mg/kg per day) for growth hormone deficiency; individualize dose based on clinical response and serum IGF-1 levels.
| Dosage form | INJECTABLE |
| Renal impairment | In patients with end-stage renal disease (GFR <15 mL/min/1.73 m²), reduce dose by 30-50% and titrate based on clinical response; monitor serum IGF-1 levels. No specific adjustments for mild-moderate renal impairment. |
| Liver impairment | No specific Child-Pugh based dose modifications are recommended; use with caution in severe hepatic impairment (Child-Pugh class C) with close monitoring of clinical response and serum IGF-1 levels. |
| Pediatric use | Growth hormone deficiency: 0.16-0.3 mg/kg subcutaneously once daily (corresponding to 0.24-0.5 IU/kg per week). Turner syndrome: 0.05 mg/kg subcutaneously once daily (0.35 mg/kg per week). Idiopathic short stature: up to 0.043 mg/kg subcutaneously once daily (0.3 mg/kg per week). Administration: rotate injection sites daily. |
| Geriatric use | Start at lower end of dosing range (0.1-0.2 mg/kg subcutaneously per day) and titrate based on clinical response and serum IGF-1 levels; monitor for adverse effects (joint pain, edema, glucose intolerance) due to increased sensitivity in elderly patients. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for HUMATROPE (HUMATROPE).
| Breastfeeding | Somatropin is not absorbed orally and is likely degraded in infant GI tract. No data on M/P ratio. Considered compatible with breastfeeding by most guidelines, but caution advised. |
| Teratogenic Risk | No malformative or feto-toxic effects observed in animal studies. Limited human data; no increased risk of congenital anomalies reported in exposed pregnancies. Theoretical risk due to IGF-1 involvement in fetal growth. Use only if clearly needed during pregnancy. |
| Fetal Monitoring |
■ FDA Black Box Warning
Increased mortality risk in patients with acute critical illness due to complications after open heart surgery, abdominal surgery, multiple accidental trauma, or acute respiratory failure. Contraindicated in pediatric patients with Prader-Willi syndrome who are severely obese or have severe respiratory impairment.
| Serious Effects |
["Acute critical illness (e.g., complications after open heart surgery, abdominal surgery, multiple trauma, acute respiratory failure)","Pediatric Prader-Willi syndrome with severe obesity or severe respiratory impairment","Active malignancy (antitumor therapy must be completed prior to initiation)","Hypersensitivity to somatropin or any excipients","Epiphyseal closure in children (for growth promotion)","Active proliferative or severe non-proliferative diabetic retinopathy"]
| Precautions | ["Increased risk of neoplasms; monitor for new growth or recurrence of preexisting tumors","Risk of intracranial hypertension (pseudotumor cerebri); fundoscopic exam recommended at initiation and periodically","Fluid retention (edema, arthralgia, carpal tunnel syndrome) more common in adults","Hyperglycemia and diabetes mellitus; monitor glucose levels","Slipped capital femoral epiphysis or Legg-Calvé-Perthes disease in children","Hypothyroidism; thyroid function tests should be performed periodically","Progression of scoliosis in children","Pancreatitis; consider in patients with abdominal pain","Lipoatrophy or lipohypertrophy at injection sites; rotate sites"] |
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| Monitor maternal blood glucose, thyroid function, and fundal height. Fetal growth ultrasound if prolonged exposure. New onset edema or hypertension warrants evaluation. |
| Fertility Effects | Somatropin may improve fertility in women with growth hormone deficiency by correcting metabolic and anovulatory states. No known direct detrimental effects on fertility. In males, may improve sperm parameters. |