Drug SummaryPharmacia and Upjohn Company
Genotropin
(somatropin (rDNA origin))
COMMON BRAND NAMES
Genotropin MiniQuick
THERAPEUTIC CLASS
Recombinant human growth hormone (hGH)
DEA CLASS
RX
ADULT DOSAGE & INDICATIONS
Growth Hormone Deficiency
Adult or Childhood-Onset Etiology:
Divide weekly dose into 6-7 SQ inj
Non Weight-Based:
Initial: 0.2mg/day (range, 0.15-0.30mg/day)
Titrate: May increase gradually every 1-2 months by increments of 0.1-0.2mg/day based on clinical response and insulin-like growth factor-I (IGF-I) concentrations
Maint: Individualize dose
Weight-Based:
Initial: Up to 0.04mg/kg/week
Titrate: May increase up to 0.08mg/kg/week at 4- to 8-week intervals based on clinical response, side effects, and determination of age- and gender-adjusted serum IGF-I concentrations
PEDIATRIC DOSAGE & INDICATIONS
Growth Hormone Deficiency
Due to an inadequate secretion of endogenous growth hormone
Individualize dose
0.16-0.24mg/kg/week; divide weekly dose into 6-7 SQ inj
Prader-Willi Syndrome
Individualize dose
0.24mg/kg/week; divide weekly dose into 6-7 SQ inj
Turner Syndrome
Individualize dose
0.33mg/kg/week; divide weekly dose into 6-7 SQ inj
Idiopathic Short Stature
Treatment of idiopathic short stature, defined by height standard deviation score ≤-2.25, and associated w/ growth rates unlikely to permit attainment of adult height in the normal range, in pediatric patients whose epiphyses are not closed and for whom diagnostic eva luation excludes other causes associated w/ short stature that should be observed or treated by other means
Individualize dose
Up to 0.47mg/kg/week; divide weekly dose into 6-7 SQ inj
Small for Gestational Age
Treatment of growth failure in children born small for gestational age who fail to manifest catch-up growth by age 2 years
Individualize dose
Up to 0.48mg/kg/week; divide weekly dose into 6-7 SQ inj
DOSING CONSIDERATIONS
Concomitant Medications
Oral Estrogen: May increase the dose requirements in women
Elderly
Consider lower starting dose and smaller dose increments
ADMINISTRATION
SQ route
May be given in the thigh, buttocks, or abdomen; the site of SQ inj should be rotated daily to help prevent lipoatrophy.
HOW SUPPLIED
Inj: (Pen cartridge) 5mg, 12mg; (MiniQuick) 0.2mg, 0.4mg, 0.6mg, 0.8mg, 1mg, 1.2mg, 1.4mg, 1.6mg, 1.8mg, 2mg [0.25mL]
CONTRAINDICATIONS
Acute critical illness due to complications following open heart surgery, abdominal surgery, multiple accidental trauma, or w/ acute respiratory failure. Pediatric patients w/ Prader-Willi syndrome (PWS) who are severely obese, have a history of upper airway obstruction or sleep apnea, or have severe respiratory impairment. Active malignancy, or evidence of progression or recurrence of an underlying intracranial tumor. Active proliferative or severe nonproliferative diabetic retinopathy. Growth promotion in pediatric patients w/ closed epiphyses. Known hypersensitivity to somatropin or any of its excipients, known sensitivity to m-cresol (pen cartridge).
WARNINGS/PRECAUTIONS
Reeva luate adults who were treated w/ somatropin for growth hormone deficiency (GHD) in childhood and whose epiphyses are closed. Treatment for short stature should be discontinued when epiphyses are fused. Implement effective weight control in patients w/ PWS and treat respiratory infections aggressively; interrupt therapy if patient shows signs of upper airway obstruction and/or new onset sleep apnea. Increased risk of a second neoplasm in childhood cancer survivors reported. Increased risk of developing malignancies in children w/ certain rare genetic causes of short stature; monitor for development of neoplasms if treatment is initiated. Monitor for increased growth, or potential malignant changes, of preexisting nevi. Undiagnosed impaired glucose tolerance and overt diabetes mellitus (DM) may be unmasked, and new-onset type 2 DM reported. Intracranial HTN (IH) w/ papilledema, visual changes, headache, N/V reported; d/c if papilledema is observed. If somatropin-induced IH is diagnosed, treatment can be restarted at a lower dose after IH-associated signs and symptoms have resolved. Fluid retention in adults may occur. Monitor other hormonal replacement treatments in patients w/ hypopituitarism. Undiagnosed/untreated hypothyroidism may prevent optimal response. Hypothyroidism may become evident or worsen. Slipped capital femoral epiphyses and progression of scoliosis may occur in pediatric patients. Increased risk of ear/hearing disorders and cardiovascular (CV) disorders in Turner syndrome (TS) patients. Tissue atrophy may occur when administered at the same site over a long period; rotate inj site. Allergic reactions may occur. Serum levels of inorganic phosphorus, alkaline phosphatase, parathyroid hormone, and IGF-I may increase. Pancreatitis rarely reported. Obese patients may manifest adverse effects when treated w/ a weight-based regimen.
ADVERSE REACTIONS
Peripheral swelling/edema, arthralgia, URI, pain/stiffness in extremities, paresthesia, headache, fatigue, myalgia, inj-site reactions/rashes, glucose intolerance, unmasking of latent central hypothyroidism.
DRUG INTERACTIONS
May inhibit 11β-hydroxysteroid dehydrogenase type 1, resulting in reduced serum cortisol concentrations; may need glucocorticoid replacement or dose adjustments of glucocorticoid therapy. Glucocorticoid therapy may attenuate growth-promoting effects in children; carefully adjust glucocorticoid replacement dosing. May increase clearance of antipyrine. May alter clearance of compounds metabolized by CYP450 liver enzymes (eg, corticosteroids, sex steroids, anticonvulsants, cyclosporine); monitor carefully. May require larger doses w/ oral estrogen replacement. May need to adjust dose of insulin and/or oral/injectable hypoglycemic agents, and thyroid hormone replacement therapy.
PREGNANCY AND LACTATION
Category B, caution in nursing.
MECHANISM OF ACTION
Recombinant hGH; stimulates linear growth in pediatrics. Normalizes concentrations of IGF-I/Somatomedin C in patients w/ GHD or PWS. Reduces fat mass, increases lean body mass, and causes metabolic alterations that include beneficial changes in lipid metabolism, and normalization of IGF-I concentrations in adults w/ GHD.
PHARMACOKINETICS
Absorption: Absolute bioavailability (80%). Administration of variable doses resulted in different parameters. Distribution: Vd=1.3L/kg. Metabolism: Liver and kidneys (protein catabolism). Elimination: T1/2=3 hrs (adults).
ASSESSMENT
Assess for signs of upper airway obstruction and sleep apnea, preexisting DM or impaired glucose tolerance, history of scoliosis, hypothyroidism, hypopituitarism, otitis media or other ear disorders in TS patients, hypersensitivity to drug or m-cresol, any other conditions where treatment is contraindicated/cautioned, pregnancy/nursing status, and possible drug interactions. Perform funduscopic exam.
MONITORING
Monitor growth, for clinical response, neoplasms, increased growth or malignant changes of preexisting nevi, IH, fluid retention, allergic reactions, pancreatitis, slipped capital femoral epiphyses and progression of scoliosis in pediatric patients (eg, onset of limp, hip or knee pain), and other adverse reactions. Perform periodic thyroid function tests, funduscopic exam, and monitoring of glucose levels. In patients w/ PWS, monitor weight as well as for signs of respiratory infections, sleep apnea, and upper airway obstruction. Monitor patients w/ history of GHD secondary to an intracranial neoplasm routinely while on therapy for progression/recurrence of tumor. In patients w/ TS, monitor for ear/CV disorders.
PATIENT COUNSELING
Inform about potential benefits and risks of therapy, proper administration, usage, and disposal, and caution against any reuse of needles and syringes.

STORAGE
(Pen cartridge) 2-8°C (36-46°F). Do not freeze. Protect from light. After reconstitution, refrigerate for up to 28 days. (MiniQuick) Refrigerate prior to dispensing, but may be stored at or below 25°C (77°F) for up to 3 months after dispensing. After reconstitution, refrigerate for up to 24 hrs before use.