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Skytrofa Dosage

Generic name: Lonapegsomatropin 3mg
Dosage form: injection, powder, lyophilized, for solution
Drug class: Growth hormones

Medically reviewed by Last updated on May 7, 2024.

General Dosing Information

  • For subcutaneous injection, once-weekly.
  • Therapy with SKYTROFA should be supervised by a physician who is experienced in the diagnosis and management of pediatric patients with growth failure due to growth hormone deficiency (GHD).
  • To exclude preexisting papilledema, perform fundoscopic examination before initiating treatment with SKYTROFA and reassess periodically thereafter [see Warnings and Precautions (5.5)].

Dosage Recommendations

  • The recommended dose of SKYTROFA for treatment-naïve patients and patients switching from daily somatropin therapy is 0.24 mg/kg body weight, given once-weekly.
  • Individualize and titrate the dosage of SKYTROFA based on response.
  • When changing from daily somatropin therapy to once-weekly SKYTROFA, wait at least 8 hours between the final dose of daily somatropin and the first dose of once-weekly SKYTROFA.
  • Assess compliance and evaluate other causes of poor growth such as hypothyroidism, under-nutrition, advanced bone age and antibodies to recombinant human growth hormone if patients experience failure to increase height velocity, particularly during the first year of treatment.
  • Discontinue SKYTROFA once epiphyseal fusion has occurred.

Missed Doses

  • Administer a missed dose as soon as possible and not more than 2 days after the missed dose.
  • To avoid missed doses, SKYTROFA can be taken 2 days before or 2 days after the scheduled dosing day. Resume once-weekly dosing for the next dose at the previously scheduled dosing day.
  • If more than 2 days have passed from the scheduled day, skip the dose and administer the next dose on the regularly scheduled day.
  • At least 5 days should elapse between doses.

Administration Instructions

SKYTROFA is available in 9 cartridges (dosage strengths in somatropin equivalents). Selection of the appropriate cartridge is based on the prescribed dose (mg/kg) and the patient's body weight (kg).

  • If prescribing a dose of 0.24 mg/kg/week and the patient's weight is 11.5 to 100 kg, follow the recommended dosing in Table 1.
  • If prescribing a dose other than 0.24 mg/kg/week, calculate the total weekly dose (in mg) and select the appropriate cartridge as follows:
    Total weekly dose (mg) = prescribed weekly dose (mg/kg) × patient's body weight (kg).
    Round the total weekly dose (mg) to the closest cartridge dose while also considering treatment goals and clinical response.
Table 1: Recommended Dosing for Patients Prescribed Doses of 0.24 mg/kg/week
Weight (kg) Dose (mg)
11.5 – 13.9 3
14 – 16.4 3.6
16.5 – 19.9 4.3
20 – 23.9 5.2
24 – 28.9 6.3
29 – 34.9 7.6
35 – 41.9 9.1
42 – 50.9 11
51 – 60.4 13.3
60.5 – 69.9 15.2 (using two cartridges of 7.6 mg each)
70 – 84.9 18.2 (using two cartridges of 9.1 mg each)
85 – 100 22 (using two cartridges of 11 mg each)

Preparation and Administration

  • The SKYTROFA cartridge has been designed for use only with the SKYTROFA Auto-Injector.
  • If refrigerated, the SKYTROFA cartridge must be kept at room temperature for 15 minutes before use.
  • The SKYTROFA Auto-Injector provides a fully automated reconstitution of the lyophilized drug product which is followed by a manual mixing step controlled by the device. When the injection needle is inserted into the skin, the device automatically delivers the drug product. The built-in electronics and software assist the user during the entire preparation and injection sequence and provide confirmation that the full dose has been delivered.
  • The mixed solution should be clear and colorless to opalescent and may occasionally contain air bubbles. DO NOT inject if the solution is cloudy or contains particulate matter.
  • Use SKYTROFA cartridges within 4 hours after reconstitution. Discard reconstituted SKYTROFA cartridges after 4 hours when stored at room temperature up to 86°F (30°C).
  • Inject SKYTROFA subcutaneously into the abdomen, buttock, or thigh. Rotate injection sites between and within regions to reduce the risk of lipoatrophy.
  • Refer to the Instructions for Use for complete administration instructions with illustrations. The instructions can also be found on

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.