Skytrofa 4.3mg Inj Cartridge
It is used to help with growth and to treat growth hormone deficiency.
Drug Class
Growth Hormone
Pharmacologic Class
Somatropin (recombinant human growth hormone), pegylated
Pregnancy Category
Not available
FDA Approved
Aug 2021
DEA Schedule
Not Controlled
Overview
What is this medicine?
Skytrofa is a medicine given as a shot once a week to children who are not growing properly because their bodies don't make enough growth hormone. It helps them grow taller.
How to Use This Medicine
Proper Administration of This Medication
To ensure your child receives this medication safely and effectively, follow the instructions provided by their doctor. Carefully read all accompanying information and adhere to the guidelines outlined below.
This medication is administered via injection into the fatty tissue of the skin, typically on the right or left side of the stomach, thigh, or buttocks. If you will be giving your child the injection, their doctor or nurse will provide personalized instruction on the proper technique.
Before administering the medication, make sure you understand the instructions for use. If you have any questions or concerns, consult with the doctor or pharmacist. If the medication has been stored in the refrigerator, allow it to reach room temperature for 15 minutes before use. Do not heat the medication.
Preparation and Administration
This medication requires mixing before use. Follow the instructions provided by the doctor for proper mixing. Rotate the injection site with each administration to minimize the risk of irritation or other complications. Avoid injecting through clothing, and do not administer the medication into skin that is irritated, bruised, red, infected, hard, or scarred.
Wash your hands thoroughly before and after handling the medication. Do not use the medication if the solution appears cloudy, is leaking, or contains particles. Additionally, do not use the medication if the solution has changed color.
After mixing, do not refrigerate the medication. Use the medication within 4 hours of preparation and discard any unused portion. Dispose of needles and other sharp objects in a designated disposal box. Do not reuse needles or other items, and follow local regulations for disposing of the full box.
Storage and Disposal
Store the medication in the refrigerator, avoiding freezing temperatures. Keep the medication in its original carton to protect it from light. If necessary, you may store the medication at room temperature for up to 6 months. Record the date you remove the medication from the refrigerator, and you may return it to the refrigerator within the 6-month period. Discard the medication if it is not used within 6 months of removal from the refrigerator.
Missed Dose
If a dose is missed, administer it as soon as possible. However, if your child misses a dose by more than 2 days, skip the missed dose and resume the normal schedule. Do not administer two doses within 5 days of each other.
To ensure your child receives this medication safely and effectively, follow the instructions provided by their doctor. Carefully read all accompanying information and adhere to the guidelines outlined below.
This medication is administered via injection into the fatty tissue of the skin, typically on the right or left side of the stomach, thigh, or buttocks. If you will be giving your child the injection, their doctor or nurse will provide personalized instruction on the proper technique.
Before administering the medication, make sure you understand the instructions for use. If you have any questions or concerns, consult with the doctor or pharmacist. If the medication has been stored in the refrigerator, allow it to reach room temperature for 15 minutes before use. Do not heat the medication.
Preparation and Administration
This medication requires mixing before use. Follow the instructions provided by the doctor for proper mixing. Rotate the injection site with each administration to minimize the risk of irritation or other complications. Avoid injecting through clothing, and do not administer the medication into skin that is irritated, bruised, red, infected, hard, or scarred.
Wash your hands thoroughly before and after handling the medication. Do not use the medication if the solution appears cloudy, is leaking, or contains particles. Additionally, do not use the medication if the solution has changed color.
After mixing, do not refrigerate the medication. Use the medication within 4 hours of preparation and discard any unused portion. Dispose of needles and other sharp objects in a designated disposal box. Do not reuse needles or other items, and follow local regulations for disposing of the full box.
Storage and Disposal
Store the medication in the refrigerator, avoiding freezing temperatures. Keep the medication in its original carton to protect it from light. If necessary, you may store the medication at room temperature for up to 6 months. Record the date you remove the medication from the refrigerator, and you may return it to the refrigerator within the 6-month period. Discard the medication if it is not used within 6 months of removal from the refrigerator.
Missed Dose
If a dose is missed, administer it as soon as possible. However, if your child misses a dose by more than 2 days, skip the missed dose and resume the normal schedule. Do not administer two doses within 5 days of each other.
Lifestyle & Tips
- Administer the injection subcutaneously (under the skin) once weekly, on the same day each week, at any time of day.
- Rotate injection sites (thighs, abdomen, buttocks, upper arms) to prevent lipoatrophy.
- Store the injection cartridge in the refrigerator (2°C to 8°C / 36°F to 46°F). Do not freeze.
- Do not shake the cartridge.
- Follow proper injection technique as instructed by your healthcare provider.
- Keep all appointments for blood tests and doctor visits to monitor growth and hormone levels.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Not indicated for adult growth hormone deficiency.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established for infants under 1 year of age.
Child:
Initial dose: 0.24 mg/kg once weekly, administered subcutaneously. Dose may be adjusted based on IGF-1 levels, up to a maximum of 0.48 mg/kg once weekly.
Adolescent:
Initial dose: 0.24 mg/kg once weekly, administered subcutaneously. Dose may be adjusted based on IGF-1 levels, up to a maximum of 0.48 mg/kg once weekly.
Dose Adjustments
Renal Impairment:
Mild:
No dose adjustment recommended.
Moderate:
No dose adjustment recommended.
Severe:
Use with caution; no specific dose recommendations available.
Dialysis:
Considerations: No specific data available; use with caution.
Hepatic Impairment:
Mild:
No dose adjustment recommended.
Moderate:
No dose adjustment recommended.
Severe:
Use with caution; no specific dose recommendations available.
Confidence:
Medium
Pharmacology
Mechanism of Action
Lonapegsomatropin-tcgd is a prodrug of somatropin. It is a long-acting C-terminally pegylated human growth hormone. After subcutaneous injection, somatropin is released from the prodrug. Somatropin binds to growth hormone (GH) receptors on target cells, stimulating linear growth, protein, carbohydrate, and lipid metabolism.
Pharmacokinetics
Absorption:
Bioavailability:
Not explicitly quantified as a percentage for the prodrug, but designed for sustained release.
Tmax:
Somatropin Tmax: Approximately 2 to 8 days after subcutaneous injection of lonapegsomatropin-tcgd.
FoodEffect:
Not applicable (parenteral administration).
Distribution:
Vd:
Somatropin Vd: Approximately 0.07 to 0.1 L/kg.
ProteinBinding:
Somatropin: Low protein binding.
CnssPenetration:
Limited
Elimination:
HalfLife:
Somatropin half-life (from lonapegsomatropin-tcgd): Approximately 25 to 48 hours.
Clearance:
Somatropin clearance: Approximately 0.002 to 0.003 L/kg/min.
ExcretionRoute:
Metabolites primarily renal.
Unchanged:
Not available
Pharmacodynamics
OnsetOfAction:
Increase in IGF-1 levels typically observed within days.
PeakEffect:
Sustained effect due to prolonged release, allowing weekly dosing.
DurationOfAction:
Approximately 7 days (due to weekly dosing regimen).
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If your child exhibits any of the following symptoms, contact their doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood sugar, including:
+ Confusion
+ Feeling sleepy
+ Unusual thirst or hunger
+ Passing urine more often
+ Flushing
+ Fast breathing
+ Breath that smells like fruit
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of a weak adrenal gland, including:
+ Severe upset stomach or vomiting
+ Severe dizziness or passing out
+ Muscle weakness
+ Feeling very tired
+ Mood changes
+ Decreased appetite
+ Weight loss
Signs of low thyroid levels, such as:
+ Constipation
+ Sensitivity to cold
+ Memory problems
+ Mood changes
+ Burning, numbness, or tingling sensations that are not normal
Signs of infection, including:
+ Fever
+ Chills
+ Severe sore throat
+ Ear or sinus pain
+ Cough
+ Increased or changed sputum production
+ Pain while urinating
+ Mouth sores
+ Wounds that will not heal
A skin lump or growth
Changes in the color or size of a mole
Skin breakdown at the site of application
Unexplained bruising or bleeding
Muscle or joint pain
Burning, numbness, pain, or tingling in the hands, arms, wrists, legs, or feet
Children using this medication can rarely experience a bone problem in the hip (slipped growth plate); seek medical attention if your child experiences hip or knee pain or a limp
Severe bone problems have occurred with this medication; contact the doctor if your child experiences new or worsening bone pain
Raised pressure in the head has rarely occurred with this medication, particularly in patients with Turner syndrome or Prader-Willi syndrome; seek medical attention if your child experiences:
+ Changes in vision
+ Severe headache
+ Upset stomach
+ Vomiting
Other Possible Side Effects
Most medications can cause side effects, but many people experience none or only mild side effects. If your child experiences any of the following side effects or any other symptoms that concern you, contact their doctor or seek medical attention:
Upset stomach or vomiting
* Stomach pain or diarrhea
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your child's doctor for medical advice.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If your child exhibits any of the following symptoms, contact their doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood sugar, including:
+ Confusion
+ Feeling sleepy
+ Unusual thirst or hunger
+ Passing urine more often
+ Flushing
+ Fast breathing
+ Breath that smells like fruit
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of a weak adrenal gland, including:
+ Severe upset stomach or vomiting
+ Severe dizziness or passing out
+ Muscle weakness
+ Feeling very tired
+ Mood changes
+ Decreased appetite
+ Weight loss
Signs of low thyroid levels, such as:
+ Constipation
+ Sensitivity to cold
+ Memory problems
+ Mood changes
+ Burning, numbness, or tingling sensations that are not normal
Signs of infection, including:
+ Fever
+ Chills
+ Severe sore throat
+ Ear or sinus pain
+ Cough
+ Increased or changed sputum production
+ Pain while urinating
+ Mouth sores
+ Wounds that will not heal
A skin lump or growth
Changes in the color or size of a mole
Skin breakdown at the site of application
Unexplained bruising or bleeding
Muscle or joint pain
Burning, numbness, pain, or tingling in the hands, arms, wrists, legs, or feet
Children using this medication can rarely experience a bone problem in the hip (slipped growth plate); seek medical attention if your child experiences hip or knee pain or a limp
Severe bone problems have occurred with this medication; contact the doctor if your child experiences new or worsening bone pain
Raised pressure in the head has rarely occurred with this medication, particularly in patients with Turner syndrome or Prader-Willi syndrome; seek medical attention if your child experiences:
+ Changes in vision
+ Severe headache
+ Upset stomach
+ Vomiting
Other Possible Side Effects
Most medications can cause side effects, but many people experience none or only mild side effects. If your child experiences any of the following side effects or any other symptoms that concern you, contact their doctor or seek medical attention:
Upset stomach or vomiting
* Stomach pain or diarrhea
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your child's doctor for medical advice.
Seek Immediate Medical Attention If You Experience:
- Severe or persistent headache, especially if accompanied by nausea, vomiting, or vision changes (e.g., blurred vision, double vision).
- Limping or new hip/knee pain.
- New or changing moles or skin lesions.
- Severe abdominal pain that does not go away.
- Signs of an allergic reaction, such as rash, hives, swelling of the face, lips, tongue, or throat, or difficulty breathing.
- Increased thirst or urination (signs of high blood sugar).
Before Using This Medicine
Before Your Child Takes This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
If your child is allergic to this medication, any of its components, or any other substances, including foods or drugs. Please describe the allergic reaction and its symptoms.
If your child has any of the following health conditions:
+ Breathing problems, such as sleep apnea
+ Cancer or other tumors, including brain tumors
+ Diabetic eye disease
+ Illness shortly after open heart surgery, stomach surgery, or accidental injury
If your child has Prader-Willi syndrome and is severely overweight, experiences breathing difficulties, or has sleep apnea
If your child's bones have stopped growing (closed epiphyses)
This list is not exhaustive, and it is crucial to discuss all your child's medications (prescription, over-the-counter, natural products, and vitamins) and health problems with the doctor and pharmacist. To ensure safe treatment, verify that it is safe to administer this medication with all your child's other medications and health conditions. Never start, stop, or adjust the dosage of any medication without consulting your doctor.
It is essential to inform your doctor about the following:
If your child is allergic to this medication, any of its components, or any other substances, including foods or drugs. Please describe the allergic reaction and its symptoms.
If your child has any of the following health conditions:
+ Breathing problems, such as sleep apnea
+ Cancer or other tumors, including brain tumors
+ Diabetic eye disease
+ Illness shortly after open heart surgery, stomach surgery, or accidental injury
If your child has Prader-Willi syndrome and is severely overweight, experiences breathing difficulties, or has sleep apnea
If your child's bones have stopped growing (closed epiphyses)
This list is not exhaustive, and it is crucial to discuss all your child's medications (prescription, over-the-counter, natural products, and vitamins) and health problems with the doctor and pharmacist. To ensure safe treatment, verify that it is safe to administer this medication with all your child's other medications and health conditions. Never start, stop, or adjust the dosage of any medication without consulting your doctor.
Precautions & Cautions
It is essential to inform all of your child's healthcare providers, including doctors, nurses, pharmacists, and dentists, that your child is taking this medication.
Your child may be at risk for high blood sugar, including the development of new-onset diabetes or worsening of existing diabetes. Monitor your child's blood sugar levels as directed by their doctor. Regular blood work and eye exams are also crucial, as scheduled by their doctor.
This medication may interfere with certain laboratory tests. Be sure to notify all healthcare providers and laboratory personnel that your child is taking this medication.
If your child experiences any changes in weight, consult with their doctor, as the dosage of this medication may need to be adjusted.
Do not share this medication, needles, or syringes with anyone, even if the needle has been changed. Sharing can lead to the transmission of infections, including those that may not be immediately apparent.
Be aware that this medication can cause fluid retention, which may lead to heart failure in some cases. If your child exhibits symptoms such as shortness of breath, significant weight gain, or swelling in the arms or legs, contact their doctor immediately.
If your child has scoliosis, consult with their doctor, as this medication may exacerbate the condition in growing children.
Children with a history of cancer or tumors should discuss the potential risks with their doctor, as this medication may increase the likelihood of cancer or tumor growth. Additionally, the development of new tumors may be a concern for some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially life-threatening respiratory problems. This risk may be increased in children with sleep apnea, lung or airway infections, airway obstruction, or obesity. Seek immediate medical attention if your child develops a fever of 100.4°F (38°C) or higher, cough, sore throat, shortness of breath, chest pain or discomfort, new or worsening snoring, or abnormal breathing patterns during sleep.
If your child is pregnant or breastfeeding, consult with their doctor to discuss the potential benefits and risks to both your child and the baby.
Your child may be at risk for high blood sugar, including the development of new-onset diabetes or worsening of existing diabetes. Monitor your child's blood sugar levels as directed by their doctor. Regular blood work and eye exams are also crucial, as scheduled by their doctor.
This medication may interfere with certain laboratory tests. Be sure to notify all healthcare providers and laboratory personnel that your child is taking this medication.
If your child experiences any changes in weight, consult with their doctor, as the dosage of this medication may need to be adjusted.
Do not share this medication, needles, or syringes with anyone, even if the needle has been changed. Sharing can lead to the transmission of infections, including those that may not be immediately apparent.
Be aware that this medication can cause fluid retention, which may lead to heart failure in some cases. If your child exhibits symptoms such as shortness of breath, significant weight gain, or swelling in the arms or legs, contact their doctor immediately.
If your child has scoliosis, consult with their doctor, as this medication may exacerbate the condition in growing children.
Children with a history of cancer or tumors should discuss the potential risks with their doctor, as this medication may increase the likelihood of cancer or tumor growth. Additionally, the development of new tumors may be a concern for some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially life-threatening respiratory problems. This risk may be increased in children with sleep apnea, lung or airway infections, airway obstruction, or obesity. Seek immediate medical attention if your child develops a fever of 100.4°F (38°C) or higher, cough, sore throat, shortness of breath, chest pain or discomfort, new or worsening snoring, or abnormal breathing patterns during sleep.
If your child is pregnant or breastfeeding, consult with their doctor to discuss the potential benefits and risks to both your child and the baby.
Overdose Information
Overdose Symptoms:
- Acute overdose may lead to initial hypoglycemia (low blood sugar) followed by hyperglycemia (high blood sugar).
- Long-term overdose may lead to signs and symptoms of gigantism/acromegaly, such as excessive growth, carpal tunnel syndrome, or other signs of overgrowth.
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. For poison control, call 1-800-222-1222.
Drug Interactions
Moderate Interactions
- Glucocorticoids
- Thyroid hormone
- Insulin and/or other antidiabetic agents
- Drugs metabolized by CYP3A4 (e.g., corticosteroids, sex steroids, cyclosporine)
Monitoring
Baseline Monitoring
Height and Weight
Rationale: To establish baseline growth parameters and calculate initial dose.
Timing: Prior to initiation of therapy.
Insulin-like Growth Factor-1 (IGF-1) and IGF Binding Protein-3 (IGFBP-3)
Rationale: To confirm growth hormone deficiency and establish baseline levels for dose titration.
Timing: Prior to initiation of therapy.
Thyroid Function (TSH, Free T4)
Rationale: To rule out hypothyroidism, which can impair response to growth hormone.
Timing: Prior to initiation of therapy.
Fasting Glucose or HbA1c
Rationale: To assess baseline glucose metabolism.
Timing: Prior to initiation of therapy.
Bone Age
Rationale: To assess skeletal maturity.
Timing: Prior to initiation of therapy.
Fundoscopic Examination
Rationale: To screen for pre-existing papilledema or other signs of intracranial hypertension.
Timing: Prior to initiation of therapy.
Routine Monitoring
Height and Weight
Frequency: Regularly (e.g., every 3-6 months)
Target: Appropriate growth velocity for age and sex.
Action Threshold: Lack of adequate growth response or excessive growth.
Insulin-like Growth Factor-1 (IGF-1)
Frequency: Every 3-6 months, or as clinically indicated for dose adjustment.
Target: Within age- and sex-appropriate reference range (typically 0 to +2 SDS).
Action Threshold: Levels consistently above or below target range, requiring dose adjustment.
Thyroid Function (TSH, Free T4)
Frequency: Periodically (e.g., annually or as clinically indicated).
Target: Normal range.
Action Threshold: Signs of hypothyroidism or hyperthyroidism.
Fasting Glucose or HbA1c
Frequency: Periodically (e.g., annually or as clinically indicated).
Target: Normal range.
Action Threshold: Elevated glucose levels.
Fundoscopic Examination
Frequency: Periodically, or if symptoms of intracranial hypertension develop.
Target: No papilledema.
Action Threshold: Presence of papilledema or other signs of intracranial hypertension.
Symptom Monitoring
- Severe or recurrent headache
- Visual changes (e.g., blurred vision, double vision)
- Nausea or vomiting
- Limping or hip/knee pain (slipped capital femoral epiphysis)
- New or worsening pigmented nevi (moles)
- Severe abdominal pain (pancreatitis)
- Signs of allergic reaction (rash, itching, swelling, difficulty breathing)
- Changes in glucose metabolism (e.g., increased thirst, urination)
Special Patient Groups
Pregnancy
Available data on lonapegsomatropin-tcgd use in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. Animal studies showed no adverse developmental effects. Endogenous growth hormone levels increase during pregnancy.
Trimester-Specific Risks:
First Trimester:
Insufficient data.
Second Trimester:
Insufficient data.
Third Trimester:
Insufficient data.
Lactation
There are no data on the presence of lonapegsomatropin-tcgd in human milk, the effects on the breastfed infant, or the effects on milk production. Endogenous growth hormone is present in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for SKYTROFA and any potential adverse effects on the breastfed infant from SKYTROFA or from the underlying maternal condition.
Infant Risk:
Risk unknown due to lack of data.
Pediatric Use
Skytrofa is indicated for the treatment of pediatric patients 1 year and older with growth hormone deficiency. Safety and effectiveness have not been established in pediatric patients less than 1 year of age.
Geriatric Use
Skytrofa is not indicated for the treatment of adult growth hormone deficiency. No studies have been conducted in geriatric patients.
Clinical Information
Clinical Pearls
- Skytrofa offers the convenience of once-weekly subcutaneous administration, which may improve adherence compared to daily growth hormone injections.
- Dose adjustments are primarily guided by IGF-1 levels, aiming to keep them within the age- and sex-appropriate reference range.
- Patients and caregivers must be thoroughly educated on proper injection technique, site rotation, and storage to ensure efficacy and minimize adverse effects.
- Close monitoring for potential adverse effects such as intracranial hypertension, slipped capital femoral epiphysis, and glucose intolerance is crucial.
- Patients with pre-existing conditions like diabetes mellitus, hypothyroidism, or a history of malignancy require careful monitoring and management while on growth hormone therapy.
Alternative Therapies
- Other recombinant human growth hormone products (somatropin) administered daily, such as Norditropin, Genotropin, Humatrope, Saizen, Omnitrope, Nutropin.
Cost & Coverage
Average Cost:
Highly variable, typically several thousand dollars per month. per cartridge
Insurance Coverage:
Specialty Tier (requires prior authorization, often subject to high co-pays or co-insurance)
General Drug Facts
If your child's symptoms or health issues persist or worsen, it is essential to contact their doctor promptly. To ensure safe and effective treatment, never share your child's medication with others, and do not administer someone else's medication to your child. Some medications may include an additional patient information leaflet; if you have any questions or concerns about this medication, consult with your child's doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call the poison control center or seek medical attention. When reporting the incident, be prepared to provide detailed information, including the substance taken, the amount, and the time it occurred.