Adult Dosing
Growth hormone deficiency (childhood or adult-onset GHD)
- Weight-based dosing
35 yrs: Start 0.006 mg/kg/day SC; may gradually increase dose q4-8 weeks to a max of 0.025 mg/kg/day- >35 yrs: Start 0.006 mg/kg/day SC; may gradually increase dose q4-8 wks to a max of 0.0125 mg/kg/day
- Non-weight-based dosing for obese individuals
- Start 0.2 mg/day (range: 0.15-0.30 mg/day) SC; may gradually increase dose q1-2 months by increments of approximately 0.1-0.2 mg/day
Notes:
- 1 mg of somatropin is equivalent to approximately 3 IU
- Administer SC injections in the thigh, upper arm, buttocks or abdomen; rotate the site of injections daily to help prevent lipoatrophy
- Consider a lower starting dose and smaller dose titration in elderly patients
Pediatric Dosing
Growth hormone deficiency (GHD)
- Pre-pubertal patients: Administer up to 0.3 mg/kg/wk SC divided daily; discontinue treatment when epiphyses close or when patient reaches satisfactory height
- Pubertal patients: Up to 0.7 mg/kg/wk SC divided into daily injections; discontinue when epiphyses close or when patient reaches satisfactory height
Growth failure secondary to chronic renal disease (CKD)
- Administer up to 0.35 mg/kg/wk SC divided 7 injections/wk; continue until the time of renal transplantation
Short stature associated with Turner Syndrome (TS)
- Up to 0.375 mg/kg/wk SC divided into equal doses 3-7 days/wk; discontinue when epiphyses close or when patient reaches satisfactory height
Idiopathic short stature (ISS)
- Administer up to 0.3 mg/kg/wk SC divided into daily injections; discontinue when epiphyses close or when patient reaches satisfactory height
Notes:- 1 mg of somatropin is equivalent to approximately 3 IU
- Administer SC injections in the thigh, buttocks, or abdomen; rotate the site of injections daily to help prevent lipoatrophy
See Supplemental Patient Information
- Therapy should be directed by physicians who are well trained in the diagnosis and management of pediatric patients with GH deficiency, chronic renal insufficiency (CRI), TS, ISS and adults with childhood-onset or adult-onset GHD
- Therapy increases mortality in patients with acute critical illness due to complications following open heart surgery, abdominal surgery, acute respiratory failure, or multiple accidental trauma. The potential benefit of treatment continuation with somatropin in patients experiencing acute critical illnesses should be weighed against the potential risk
- Fatalities have been reported following therapy initiation in pediatric patients with PWS who had one or more of the following risk factors including severe obesity, unidentified respiratory infection, or history of upper airway obstruction or sleep apnea; male patients with one or more of these factors are more prone to such fatalities
- Evaluate patients with PWS for signs of upper airway obstruction and sleep apnea before treatment initiation with somatropin; interrupt therapy if such signs develop during treatment (including onset of or increased snoring and/or new onset sleep apnea)
- Effective weight control measures should be considered in patients with PWS treated with somatropin. Monitor for signs of respiratory infection, which should be diagnosed at the earliest and treated aggressively
- Routinely examine patients with preexisting tumors or GHD secondary to an intracranial lesion for progression or recurrence of the underlying disease process. Increased risk of a second neoplasm has been reported in childhood cancer survivors treated with somatropin following their first neoplasm. Intracranial tumors, particularly meningiomas, have occurred in patients treated with radiation to the head for their first neoplasm. Carefully monitor patients for any malignant transformation of skin lesions
- Therapy may decrease insulin sensitivity, particularly at higher doses in susceptible patients. Monitor glucose levels periodically in all patients receiving therapy, especially in those with risk factors for diabetes mellitus, including obesity, TS, or a family history of diabetes mellitus. Closely monitor patients with preexisting type 1 or type 2 diabetes mellitus or impaired glucose tolerance; if required, adjust doses of antihyperglycemic drugs when somatropin therapy is initiated in these patients
- Mean fasting and postprandial insulin levels increased, while mean fasting and postprandial glucose levels remained unchanged in patients receiving therapy for ISS. Also, mean hemoglobin A1c levels increased slightly from baseline as expected during adolescence; sporadic values outside normal limits have occurred transiently
- Intracranial hypertension (IH) with papilledema, visual changes, headache, and other signs have been reported with somatropin therapy; perform funduscopic examination before initiating treatment to exclude preexisting papilledema and periodically during the course of somatropin therapy
- Discontinue treatment if papilledema is observed by funduscopy and restart at a lower dose after IH-associated signs and symptoms have resolved
- Patients with TS, CKD, and PWS are more susceptible for the development of IH
- Fluid retention may occur in adult patients during somatropin replacement therapy
- Closely monitor patients with hypopituitarism (multiple pituitary hormone deficiencies) during somatropin treatment
- Undiagnosed/untreated hypothyroidism may prevent an optimal response to somatropin, particularly the growth response in children. Patients with TS posses an increased risk of developing autoimmune thyroid disease and primary hypothyroidism
- Periodically perform thyroid function tests during therapy; initiate thyroid hormone replacement therapy or appropriately adjust the dose when indicated
- Pediatric patients with the onset of a limp or complaints of hip or knee pain during somatropin therapy should be carefully evaluated, as slipped capital femoral epiphyses may occur more frequently in patients with endocrine disorders or in patients undergoing rapid growth
- Patients with a history of scoliosis who are treated with somatropin should be monitored for progression of scoliosis as somatropin increases growth rate. Scoliosis is commonly seen in untreated patients with PWS; hence, physicians should be alert to these abnormalities, which may manifest during therapy
- Periodically examine children with growth failure secondary to chronic renal insufficiency for evidence of progression of renal osteodystrophy. Obtain X-rays of the hip prior to initiating somatropin therapy in CKD patients. Therapy not indicated for treatment of patients with functioning renal allografts
- Therapy may be associated with an increased risk of ear and hearing disorders. Therefore, patients with TS should be evaluated carefully for otitis media and other ear disorders. Closely monitor patients with TS for cardiovascular disorders such as stroke, hypertension, and aortic aneurysm as they are at an increased risk for these conditions
- Local or systemic allergic reactions may occur during therapy. Inform parents/patients that such reactions are possible and prompt medical attention should be sought on occurrence of these allergic reactions
- Rotate the injection site of somatropin as it can cause tissue atrophy if administered subcutaneously at the same site over a long period of time
- Patients treated with somatropin replacement therapy in childhood should be reevaluated before continuation of somatropin therapy at the reduced dose level recommended for GH deficient adults
- Rare cases of pancreatitis have been reported in children and adults receiving therapy; girls with TS are more susceptible to this risk
- Serum levels of inorganic phosphorus, alkaline phosphatase, parathyroid hormone (PTH) and IGF-I may increase during somatropin therapy
- Benzyl alcohol used as a preservative in bacteriostatic normal saline may be associated with serious adverse events and death, particularly in newborns
Cautions: Use cautiously in:
Supplemental Patient Information
- Inform patients and caregivers about the potential benefits and risks associated with somatropin therapy
- Instruct patients and caregivers regarding the importance of proper disposal of used needles and syringes; strongly recommend a puncture-resistant container for the disposal of such materials
Pregnancy Category:C
Breastfeeding: Safety unknown. Limited data indicate that exogenous somatropin is not expected to cause any adverse effects in breastfed infants of mothers who receive somatropin. This information is based upon LactMed database (available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT last accessed 2 February 2011). Manufacturer advises caution.
