BIO-TROPIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BIO-TROPIN (BIO-TROPIN).
Recombinant human growth hormone (somatropin) that binds to growth hormone receptors, activating JAK-STAT signaling and downstream pathways promoting linear growth, protein synthesis, and lipolysis.
| Metabolism | Primarily hepatic; metabolized via proteolysis. |
| Excretion | Renal excretion: >90% as intact growth hormone; biliary/fecal: negligible (<1%). |
| Half-life | Terminal half-life: 2-4 hours (IV); due to rapid clearance, clinical effects persist via downstream mediators (IGF-1). |
| Protein binding | ~50% bound; growth hormone-binding protein (GHBP) and albumin. |
| Volume of Distribution | 0.05-0.1 L/kg; limited to extracellular fluid, indicating low tissue penetration. |
| Bioavailability | Subcutaneous: 80% (compared to IV); intramuscular: 50-60%. |
| Onset of Action | Subcutaneous: 2-4 hours for initial metabolic effects (lipolysis, protein synthesis); IV: 30 minutes. |
| Duration of Action | Subcutaneous: 18-24 hours (once-daily dosing maintains therapeutic IGF-1 levels); IV: 6-8 hours. |
0.1-0.2 mg/kg subcutaneously 3 times per week for adult growth hormone deficiency; for AIDS wasting, 0.1 mg/kg subcutaneously daily
| Dosage form | INJECTABLE |
| Renal impairment | No specific dosing adjustment required for renal impairment; monitor for fluid retention |
| Liver impairment | No specific Child-Pugh based adjustments; use caution in severe hepatic impairment |
| Pediatric use | 0.18-0.3 mg/kg per week subcutaneously divided into daily doses for growth hormone deficiency |
| Geriatric use | Start at lower dose (0.1-0.2 mg/kg per week subcutaneously divided into 3-7 doses) due to increased risk of adverse effects; titrate based on clinical response and IGF-1 levels |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BIO-TROPIN (BIO-TROPIN).
| Breastfeeding | Unknown if somatropin is excreted in human milk; limited data suggests low levels; M/P ratio not determined. Risk to infant cannot be excluded; consider developmental and health benefits of breastfeeding along with mother's clinical need and potential adverse effects on the infant. |
| Teratogenic Risk | First trimester: Limited human data; animal studies show no evidence of teratogenicity at doses up to 3 times the human dose. Second and third trimesters: Somatropin does not cross the placenta in significant amounts; no known increase in congenital anomalies, but cases of fetal growth restriction and stillbirth reported in growth hormone deficiency pregnancies; caution advised. |
■ FDA Black Box Warning
Increased mortality in patients with acute critical illness due to complications following open heart surgery, abdominal surgery, or multiple accidental trauma. Not approved for use in these conditions.
| Serious Effects |
["Acute critical illness (post-surgery, trauma, respiratory failure)","Active malignancy","Diabetic retinopathy (particularly proliferative)","Children with closed epiphyses","Hypersensitivity to somatropin or excipients","Prader-Willi syndrome with severe obesity or respiratory impairment"]
| Precautions | ["Increased risk of malignancies (monitor for recurrence)","Benign intracranial hypertension (papilledema, headache, vision changes)","Slipped capital femoral epiphysis in children and Avascular necrosis","Pancreatitis","Fluid retention (edema, arthralgia, carpal tunnel syndrome)","Glucose intolerance and diabetes mellitus","Hypoadrenalism in patients with ACTH deficiency"] |
| Food/Dietary | No specific food interactions. Maintain balanced diet to support growth. Avoid excessive intake of simple sugars as growth hormone can impair glucose tolerance. |
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| Fetal Monitoring | Monitor maternal blood pressure, blood glucose, and thyroid function throughout pregnancy. Monitor fetal growth by ultrasound every 4-6 weeks due to potential growth restriction. Assess for signs of acromegaly if overtreated. |
| Fertility Effects | In women with growth hormone deficiency, somatropin may restore fertility by improving ovarian response to gonadotropins. In men, may improve spermatogenesis. No known adverse effects on fertility when used therapeutically. |
| Clinical Pearls | Bio-Tropin (somatropin) is a recombinant human growth hormone. Administer subcutaneously, rotating injection sites to prevent lipoatrophy. Screen for secondary hypothyroidism and monitor thyroid function tests; growth hormone can unmask central hypothyroidism. Monitor for increased intracranial pressure (pseudotumor cerebri) especially in patients with risk factors. Dose should be individualized based on growth response and serum IGF-1 levels. Use with caution in patients with diabetes mellitus as growth hormone is hyperglycemic. |
| Patient Advice | Inject Bio-Tropin subcutaneously at the same time each day, preferably in the evening. · Rotate injection sites: abdomen, thigh, buttock; do not inject into the same area repeatedly. · Store Bio-Tropin in the refrigerator at 2-8°C; do not freeze. Reconstituted solution can be stored for up to 14 days. · Report symptoms of increased intracranial pressure: severe headache, visual changes, nausea/vomiting. · Monitor for signs of hyperglycemia: increased thirst, frequent urination, fatigue. · Do not stop treatment abruptly; consult your doctor before discontinuing. |