Genotropin (somatropin)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Somatropin is a recombinant human growth hormone (hGH) with an amino acid sequence identical to that of hGH of pituitary origin.
Somatropin (recombinant) is a human growth hormone (hGH) prepared using recombinant DNA technology, with an amino acid sequence identical to that of human growth hormone of pituitary origin.
Somatropin binds to the hGH receptor in the cell membrane of target cells resulting in a cascade of direct and indirect pharmacodynamic effects including normalization of insulin-like growth factor-1 (IGF-1) concentrations, stimulation of chondrocyte differentiation and proliferation, stimulation of hepatic glucose output, protein synthesis, and lipolysis.
The stimulation of skeletal growth increases linear growth rate (height velocity) in most somatropin-treated pediatric patients (e.g., growth hormone deficiency (GHD), Turner syndrome, small for gestational age, idiopathic short stature, chronic kidney disease (CKD), Prader-Willi syndrome). In adults with GHD, somatropin treatment results in reduced fat mass, increased lean body mass, metabolic alterations that include beneficial changes in lipid metabolism, reduction in body fat stores, and normalization of IGF-1 concentrations. In adults with HIV-associated wasting or cachexia, somatropin treatment results in improved nitrogen balance and increased protein-sparing lipid oxidation; decreased trunk fat, decreased total body fat, and increased lean body mass were observed in these patients.
The absolute bioavailability of somatropin after subcutaneous injection ranges between 70-90%. Somatropin undergoes protein catabolism in both the liver and kidneys; extensive metabolism studies have not been conducted. In pharmacokinetic studies of various somatropin preparations in various patient populations (e.g., adult GHD, HIV-associated wasting) or healthy volunteers, the half-life of subcutaneously administered somatropin ranged from 2 to 10 hours; the median reported half-life was 3 hours.
Limited published pharmacokinetic data do not suggest differences in somatropin plasma clearance and average steady-state plasma concentrations between young and elderly patients. Available published literature suggests that somatropin clearance is similar in adults and pediatric patients; no pharmacokinetic studies have been conducted in pediatric patients with HIV. Available literature suggests somatropin clearance may be similar or higher in males, however sex-based analysis is not available in normal volunteers or patients infected with HIV.
Decreased somatropin clearance has been observed in children and adults with CKD and end-stage renal disease (ESRD); in a study of 6 pediatric patients (7-11 years of age) somatropin clearance was reduced 22.6% after subcutaneous injection compared to normal healthy adults. Somatropin accumulation has not been reported at this time in children with CKD or ESRD dosed with current regimens. Reduced somatropin clearance has been noted in patients with severe liver dysfunction; the clinical significance of this is unknown.
Somatropin clearance and mean terminal half-life in healthy adults and children are similar to patients with GHD.
Somatropin is used in the treatment of short stature or growth failure due to growth hormone deficiency or other conditions. Another indication for the drug includes the treatment of HIV patients with wasting or cachexia. There are multiple recombinant growth hormone preparations commercially available in the US.
Although clinically similar, differences exist among the products in FDA-approved indications, administration, and dosing schedules. Disease-specific treatment risks also vary among the various growth failure indications; consult guidelines and preparation-specific labeling for additional guidance.
Generic name: somatropin
Pronunciation: (so-mah-TROW-pin)
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Genotropin
Indications
The following indications are listed for Genotropin:
- Adult Growth Hormone Deficiency
- Growth Failure Associated With Turner's Syndrome
- Growth Failure Due To Prader-Willi Syndrome
- Idiopathic Short Stature
- Pituitary Dwarfism
- Short Stature Associated With Noonan Syndrome
- Short Stature In Child Born Small For Gestational Age
Also known as: Adult Gh Deficiency, Child Born Small For Gestational Age Without Catch-Up Growth, Gh Deficiency Dwarfism, Growth Failure Due To Isolated Growth Hormone Deficiency, Growth Failure Due To Isolated Somatotropin Deficiency, Growth Failure Due To Pws, Growth Failure In Child With Prader-Willi Syndrome, Growth Failure In Child With Turner's Syndrome, Growth Failure In Pediatric Patient With Prader-Willi Syndrome, Growth Failure In Pediatric Patient With Turner's Syndrome, Hypophysial Dwarfism, Idiopathic Non-Growth Hormone Deficiency Short Stature, Lorain-Levi Dwarfism, Lorain-Levi Infantilism, Lorain-Levi Syndrome, Pituitary Infantilism, Short Sga Child, Short Stature Associated With Noonan's Syndrome, Short Stature In Child With Noonan Syndrome, Short Stature In Pediatric Patient With Noonan Syndrome, Short Stature In Pediatric Patient With Turner's Syndrome.
Dosing
No dosing information is available for this tab.
Somatropin is administered by subcutaneous injection. Subcutaneous injections should be made into the back of the upper arm, abdomen, buttock, or thigh with regular rotation of injection sites to avoid lipoatrophy.
Somatropin is commercially available in various dosage forms for subcutaneous administration including single-dose or multi-dose vial kits containing lyophilized powder and diluent vials, two-chamber cartridges containing lyophilized powder and diluent, and cartridge kits containing lyophilized powder and diluent in prefilled syringes; all powder formulations require reconstitution prior to administration, and some require product specific delivery devices.
Somatropin is also available as a solution for subcutaneous administration in ready-to-use prefilled pens, injection devices, or cartridges.
Prior to the first injection of somatropin, store preparations and diluent (if supplied) at 2-8degreesC in the original carton for protection from light and physical damage; exceptions include storing Serostim(R) at 15-30degreesC until the expiration date on the manufacturer's label and Genotropin Miniquick(R), which may be stored at or below 25degreesC for up to 3 months after dispensing. Avoid storage under conditions of extreme heat or cold, and do not shake or freeze the drug; protect from light.
Patients and/or their caregivers should be cautioned against sharing or reusing syringes, needles, and/or devices. Carefully instruct patients on the proper, safe disposal of needles, syringes, and unused drug. Patients should be supplied with a puncture-resistant container for the proper, safe disposal of such equipment after use.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
Somatropin is not known to be metabolized by cytochrome P-450 (CYP) isoenzymes or other drug metabolizing enzymes, however growth hormone can induce changes in CYP activity.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
*Acute critical illness after open heart surgery, abdominal surgery, or multiple accidental trauma, or acute respiratory failure.
*Hypersensitivity to somatropin or any of the excipients.
*Active malignancy.
*Active proliferative or severe non-proliferative diabetic retinopathy.
*Pediatric patients with closed epiphyses.
*Pediatric patients with Prader-Willi syndrome who are severely obese, have a history of upper airway obstruction or sleep apnea or have severe respiratory impairment, due to the risk of sudden death.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
Common adverse reactions reported in adult and pediatric patients receiving somatropin include upper respiratory infection, fever, pharyngitis, headache, injection site reactions (such as pain, numbness, redness, and swelling), rashes, lipoatrophy, otitis media, edema, flatulence, abdominal pain, arthralgia, carpal tunnel syndrome, paresthesia, myalgia, peripheral edema, flu syndrome, and impaired glucose tolerance.
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
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Safety and efficacy of somatropin for the management of children with growth failure due to inadequate secretion of endogenous growth hormone are supported by 3 open-label, multicenter trials conducted over a duration of 2 years (2 trials) and 8 years (1 trial).
Safety and efficacy of somatropin for the management of children with short stature associated with Turner syndrome are supported by one long-term, randomized, dose-response study and 3 long-term, open-label, multicenter studies with concurrent or historical controls.
Safety and efficacy of somatropin for the management of children with idiopathic short stature are supported by one dose-response study, one placebo-controlled study, and 3 randomized studies.
Safety and efficacy of somatropin for the management of children with short stature or growth failure in SHOX deficiency are supported by a single randomized, controlled, 2-year, 3-arm, open-label study in 52 patients.
Safety and efficacy of somatropin for the management of short stature in children born small for gestational age with no catch-up growth by 2 to 4 years of age are supported by 4 clinical studies. One study was a randomized, double-blind, 2-arm study and another was a randomized study of prepubertal, non-GHD, Japanese pediatric patients.
Safety and efficacy of somatropin for the management of short stature associated with Noonan syndrome are supported by a prospective, open-label, randomized, parallel group, 2-year study in 21 pediatric patients.
Safety and efficacy of somatropin for the management of growth failure due to Prader-Willi syndrome are supported by 2 randomized, open label, controlled clinical trials. Sudden death after somatropin initiation has been reported in pediatric patients with Prader-Willi syndrome who had at least one of the following risk factors: severe obesity, history of upper airway obstruction or sleep apnea, or unidentified respiratory infection.
Safety and efficacy of somatropin in pediatric patients with HIV have not been established. Treatment appeared to be well tolerated and consistent with safety observations of adults treated with somatropin for HIV-associated wasting in 2 small studies of 11 children with HIV-associated failure to thrive who received somatropin 0.04 mg/kg per day for 26 weeks or somatropin 0.07 mg/kg per day for 4 weeks.
Risks of growth hormone therapy specific to pediatric patients include risk of sudden death in pediatric patients with Prader-Willi syndrome, increased risk of second neoplasm in pediatric cancer survivors treated with radiation to the brain and/or head, intracranial hypertension, slipped capital femoral epiphysis, progression of preexisting scoliosis, and pancreatitis.
Benzyl alcohol may be a component of somatropin products or the diluent used for reconstitution. Benzyl alcohol has been associated with serious adverse events and death; ''gasping syndrome,'' (characterized by CNS depression, metabolic acidosis, gasping respirations, and high levels of benzyl alcohol and its metabolites found in the blood and urine) has been associated with dosages >99 mg/kg per day in neonates and low-birth weight neonates. Additional symptoms may include gradual neurological deterioration, seizures, intracranial hemorrhage, hematologic abnormalities, skin breakdown, hepatic and renal failure, hypotension, bradycardia, and cardiovascular collapse. The combined daily metabolic load of benzyl alcohol from all sources should be considered. To decrease benzyl alcohol exposure in high-risk patients, consult the preparation-specific labeling to find a benzyl alcohol-free product or alternative diluents.
Available data with somatropin use in pregnant women are insufficient to determine a drug-associated risk of adverse developmental outcomes or any impact on reproductive capacity.
The American Association of Clinical Endocrinologists (AACE)/American College of Endocrinology (ACE) and Endocrine Society guidelines state that due to insufficient evidence of safety or efficacy, routine use of somatropin for conception or continued use during pregnancy in women with GHD is not recommended.
Benzyl alcohol is rapidly metabolized in pregnancy; therefore, exposure to the fetus is unlikely. Intravenously administered drugs containing benzyl alcohol have caused adverse reactions in premature neonates and low birth weight infants. To avoid fetal exposure to benzyl alcohol in women continuing somatropin during pregnancy, consult the preparation-specific labeling to find a benzyl alcohol-free product or alternative diluents.
Animal reproduction studies were conducted with various somatropin preparations at doses in excess of normal human doses (e.g., 1 mg/kg per day, 3.3 mg/kg per day), resulting in growth hormone blood levels in excess of human therapeutic levels (e.g., 19 and 24 times higher, respectively), and administered at different time frames corresponding to the periods of organogenesis or gametogenesis. No adverse effects were observed on gestation, morphogenesis, parturition, lactation, postnatal development, or reproductive capacity of the offspring.
There is no information regarding the presence of somatropin in human milk; limited data indicate that exogenous somatropin does not increase normal breastmilk concentrations of growth hormone, and no adverse effects on the breastfed infant have been reported with somatropin.
Consider the benefits of breast-feeding and the importance of somatropin to the woman along with the potential adverse effects on the breast-fed infant from the drug or underlying maternal condition.
Benzyl alcohol is rapidly metabolized in lactating women; therefore, exposure in the breast-fed infant is unlikely. Intravenously administered drugs containing benzyl alcohol have caused adverse reactions in premature neonates and low birth weight infants.
To avoid infant exposure to benzyl alcohol from women continuing somatropin while breast-feeding, consult the preparation-specific labeling to find a benzyl alcohol-free product or alternative diluents.
Elderly patients may be more sensitive to somatropin and may be more prone to develop adverse reactions; lower initial doses and smaller dose adjustment increments are recommended.
Experience in patients >=65 years of age is insufficient to determine whether they respond differently to somatropin than younger patients.
Elderly patients may be more sensitive to somatropin, may be more prone to develop adverse reactions, and lower initial doses with smaller dosage adjustment increments are recommended.
ICD codes
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Last reviewed · Source: First Databank (FDB) drug data
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