Generic name: somatropin
Dosage form: injection
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For subcutaneous injection.
Therapy with Humatrope should be supervised by a physician who is experienced in the diagnosis and management of pediatric patients with short stature associated with GH deficiency, Turner syndrome, idiopathic short stature, SHOX deficiency, small for gestational age birth, or adult patients with either childhood-onset or adult-onset GH deficiency.
Vial — Each 5-mg vial of Humatrope should be reconstituted with 1.5 to 5 mL of Diluent for Humatrope. The diluent should be injected into the vial of Humatrope by aiming the stream of liquid gently against the vial wall. Following reconstitution, the vial should be swirled with a GENTLE rotary motion until the contents are completely dissolved. DO NOT SHAKE. The resulting solution should be clear. If the solution is cloudy or contains particulate matter, the contents MUST NOT be injected.
If sensitivity to the diluent should occur, the vials may be reconstituted with Bacteriostatic Water for Injection (Benzyl Alcohol preserved), USP or Sterile Water for Injection, USP. When Humatrope is reconstituted with Bacteriostatic Water for Injection, USP, the solution should be kept refrigerated at 36° to 46°F (2° to 8°C) and used within 14 days. It is important to note that benzyl alcohol used as a preservative in Bacteriostatic Water has been associated with toxicity in newborns. Therefore, Bacteriostatic Water for Injection must not be used to reconstitute Humatrope for use in a newborn infant. When Humatrope is to be administered to a newborn infant it should be reconstituted with the diluent provided or, if the infant is sensitive to the diluent, Sterile Water for Injection, USP. When reconstituted with Sterile Water for Injection the solution should be kept refrigerated at 36° to 46°F (2° to 8°C) and used within 24 hours.
Cartridge — The Humatrope cartridge has been designed for use only with the Humatrope injection device. Each cartridge of Humatrope should be reconstituted using only the diluent syringe that accompanies the cartridge and should not be reconstituted with the Diluent for Humatrope provided with Humatrope vials. The reconstituted solution should be clear. If the solution is cloudy or contains particulate matter, the contents MUST NOT be injected. Humatrope cartridges should not be used if the patient is allergic to metacresol or glycerin.
The somatropin concentrations for the reconstituted Humatrope cartridges are as follows:
|6 mg cartridge (gold)||2.08 mg/mL|
|12 mg cartridge (teal)||4.17 mg/mL|
|24 mg cartridge (purple)||8.33 mg/mL|
[See How Supplied (16.2) and Information for the Patient for comprehensive directions on Humatrope cartridge reconstitution].
General Administration Guidelines
For all indications, the following general principles for administration should be followed:
- When using the Humatrope vial the septum of the vial should be wiped with an alcoholic antiseptic solution before and after each injection to prevent contamination of the contents by repeated needle insertions. Sterile disposable syringes and needles should be used. The volume of the syringe should be small enough so that the prescribed dose can be withdrawn from the vial with reasonable accuracy.
- When using the Humatrope cartridge a sterile disposable needle should be used for each injection.
- Humatrope should be administered by subcutaneous injection with regular rotation of injection sites to avoid lipoatrophy.
- For pediatric patients the calculated weekly Humatrope dosage should be divided into equal doses given either 6 or 7 days per week.
- For adult patients the prescribed dose should be administered daily.
Dosing for Pediatric Patients
The Humatrope dosage and administration schedule should be individualized for each patient based on the growth response. Failure to increase height velocity, particularly during the first year of treatment, should prompt close assessment of compliance and evaluation of other causes of poor growth, such as hypothyroidism, under-nutrition, advanced bone age and antibodies to recombinant human growth hormone. Response to somatropin treatment tends to decrease with time. Somatropin treatment for stimulation of linear growth should be discontinued once epiphyseal fusion has occurred.
The recommended weekly dosages in milligrams (mg) per kilogram (kg) of body weight for pediatric patients are:
a Recent literature has recommended initial treatment with larger doses of somatropin (e.g., 0.067 mg/kg/day), especially in very short children (i.e., height SDS <–3), and/or older pubertal children, and that a reduction in dosage (e.g., gradually towards 0.033 mg/kg/day) should be considered if substantial catch-up growth is observed during the first few years of therapy. On the other hand, in younger SGA children (e.g., approximately <4 years) (who respond the best in general) with less severe short stature (i.e., baseline height SDS values between -2 and -3), consideration should be given to initiating treatment at a lower dose (e.g., 0.033 mg/kg/day), and titrating the dose as needed over time. In all children, clinicians should carefully monitor the growth response, and adjust the somatropin dose as necessary.
|Growth hormone deficiency||0.026 to 0.043 mg/kg/day (0.18 to 0.30 mg/kg/week)|
|Turner syndrome||up to 0.054 mg/kg/day (0.375 mg/kg/week)|
|Idiopathic short stature||up to 0.053 mg/kg/day (0.37 mg/kg/week)|
|SHOX deficiency||0.050 mg/kg/day (0.35 mg/kg/week)|
|Small for gestational age||up to 0.067 mg/kg/day (0.47 mg/kg/week)a|
Dosing for Patients with Adult Growth Hormone Deficiency
Either of two approaches to Humatrope dosing may be followed: a non-weight-based regimen or a weight-based regimen.
Non-weight based — based on published consensus guidelines, a starting dose of approximately 0.2 mg/day (range, 0.15-0.30 mg/day) may be used without consideration of body weight. This dose can be increased gradually every 1-2 months by increments of approximately 0.1-0.2 mg/day, according to individual patient requirements based on the clinical response and serum insulin-like growth factor I (IGF-I) concentrations. The dose should be decreased as necessary on the basis of adverse events and/or serum IGF-I concentrations above the age- and gender-specific normal range. Maintenance dosages vary considerably from person to person, and between male and female patients.
Weight-based — based on the dosing regimen used in the original adult GH deficiency registration trials, the recommended dosage at the start of treatment is not more than 0.006 mg/kg (6 μg/kg) daily. The dose may be increased according to individual patient requirements to a maximum of 0.0125 mg/kg (12.5 μg/kg) daily. Clinical response, side effects, and determination of age- and gender-adjusted serum IGF-I concentrations should be used as guidance in dose titration.
A lower starting dose and smaller dose increments should be considered for older patients, who are more prone to the adverse effects of somatropin than younger individuals. In addition, obese individuals are more likely to manifest adverse effects when treated with a weight-based regimen. Estrogen-replete women may need higher doses than men. Oral estrogen administration may increase the dose requirements in women.