What are the preparation, administration, duration, side effects, and cost of growth hormone (GH) injection therapy?

Growth Hormone Injection: Preparation, Administration, Duration, Side Effects, and Cost

Growth hormone (GH) should be administered at a dose of 0.045-0.05 mg/kg body weight per day via subcutaneous injections in the evening until the patient reaches their final height or until renal transplantation in cases of chronic kidney disease. 1

Preparation and Administration

Dosing

• For children with chronic kidney disease (CKD): 0.045-0.05 mg/kg/day subcutaneously 1
• For children with growth hormone deficiency: Up to 0.3 mg/kg/week divided into daily injections 2
• For adults with growth hormone deficiency: Starting dose not more than 0.006 mg/kg daily, with potential increases to a maximum of 0.025 mg/kg daily in patients ≤35 years 2

Administration Technique

• Subcutaneous injection is the recommended route 1, 2, 3
• Evening administration is preferred to mimic physiological circadian rhythm of GH secretion 1
• Injection sites should be rotated daily to avoid lipoatrophy 3
• For patients on dialysis, specific timing recommendations apply 2:
  • Hemodialysis patients: Inject at night before sleep or 3-4 hours after hemodialysis
  • CCPD patients: Inject in morning after completing dialysis
  • CAPD patients: Inject in evening during overnight exchange

Self-Administration

• Children from 8-10 years of age can be taught to self-administer injections with proper training and supervision 1
• Both GH reference and biosimilar products are recommended for use 1

Duration of Treatment

• Treatment continues until:
  • Epiphyseal closure is demonstrated (growth plates close) 1, 3
  • Patient reaches final height 1
  • At the time of renal transplantation in CKD patients 1, 2
• Expected increase in final height after 2-5 years of GH treatment is approximately 7.2 cm 1
• Treatment response should be monitored every 3-6 months 1

Side Effects and Safety Monitoring

Common Side Effects

• Injection site reactions and rashes 3
• Lipoatrophy at injection sites 3
• Headaches 3
• Fluid retention (edema, arthralgia, carpal tunnel syndrome) - especially in adults 3

Serious Adverse Effects (Rare)

• Intracranial hypertension (requires immediate discontinuation) 1, 3
• Glucose intolerance and potential unmasking of diabetes mellitus 1, 3
• Slipped capital femoral epiphysis 1, 3
• Aggravation of secondary hyperparathyroidism in CKD patients 1
• Progression of preexisting scoliosis 3
• Pancreatitis (consider in patients with persistent severe abdominal pain) 3

Contraindications

• Closed epiphyses (no growth potential) 1, 3
• Active malignancy 1, 3
• Acute critical illness 3
• Severe secondary hyperparathyroidism (PTH >500 pg/ml) in CKD patients 1
• Proliferative or severe non-proliferative diabetic retinopathy 1, 3
• Hypersensitivity to somatropin or excipients 3

Monitoring Requirements

• Height velocity and growth parameters every 3-6 months 1
• Pubertal development and skeletal maturation (wrist radiography) 1
• Thyroid function (TSH and free T3) 1
• Glucose metabolism 1, 3
• Calcium, phosphate, bicarbonate, and parathyroid hormone levels (especially in CKD) 1
• If height velocity in first year is less than 2 cm/year over baseline, assess:
  • Adherence to therapy
  • Serum IGF-1 levels
  • Weight-adjusted dosage
  • Nutritional and metabolic factors 1

Cost Considerations

• GH therapy is expensive, with significant cost implications for healthcare systems
• Cost-effectiveness analysis should be considered when making treatment decisions 1
• Both reference and biosimilar products are available, with biosimilars potentially offering cost advantages 1
• Treatment should be prioritized for children with severe growth failure where evidence supports improved outcomes 4

Clinical Pitfalls and Caveats

• Individual growth responses to GH therapy vary widely; patients and families should be informed of this before starting treatment 1
• GH therapy should be stopped at the time of renal transplantation 1
• In patients with persistent severe secondary hyperparathyroidism (PTH >500 pg/ml), GH should be withheld until PTH levels return to target range 1
• Close monitoring of glucose metabolism is essential, particularly in patients with risk factors for diabetes 1, 3
• Patients with nephropathic cystinosis have increased risk of diabetes mellitus regardless of GH treatment 1
• The benefits of increased stature must be weighed against the burden of daily injections on an individual basis 1