Skytrofa 3mg Inj Cartridge
It is used to help with growth and to treat growth hormone deficiency.
Drug Class
Growth Hormone
Pharmacologic Class
Somatropin (long-acting)
Pregnancy Category
Not available
FDA Approved
Aug 2021
DEA Schedule
Not Controlled
Overview
What is this medicine?
Skytrofa is a medicine that helps children with growth hormone deficiency grow taller. It's a long-acting form of growth hormone, so it only needs to be injected once a week instead of daily.
How to Use This Medicine
Administering This Medication
To ensure your child receives this medication correctly, follow the instructions provided by their doctor. Carefully read all accompanying information and follow the instructions precisely. This medication is administered via injection into the fatty tissue 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 guidance on the proper technique. It is essential that you understand how to use this medication. Refer to the instructions for use that come with the medication, and if you have any questions or concerns, consult with the doctor or pharmacist.
Before administering the medication, remove it from the refrigerator and let it reach room temperature for 15 minutes. Do not heat the medication. As instructed by the doctor, mix the medication before use.
Important Administration Guidelines
Rotate the injection site with each dose to avoid tissue damage.
Do not inject the medication through clothing.
Avoid injecting into skin that is irritated, bruised, red, infected, hard, or scarred.
Wash your hands before and after handling the medication.
Do not use the medication if the solution appears cloudy, is leaking, or contains particles.
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.
* Dispose of needles and other sharp objects in a designated disposal box. Do not reuse needles or other items. When the box is full, follow local regulations for disposal. If you have any questions, consult with a doctor or pharmacist.
Storage and Disposal
Store the medication in a refrigerator at a temperature between 2°C and 8°C (36°F and 46°F). Do not freeze. 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. You may return the medication 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 you miss a dose, administer it as soon as you remember. However, if your child misses a dose by more than 2 days, skip the missed dose and resume the regular schedule. Do not administer two doses within 5 days of each other.
To ensure your child receives this medication correctly, follow the instructions provided by their doctor. Carefully read all accompanying information and follow the instructions precisely. This medication is administered via injection into the fatty tissue 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 guidance on the proper technique. It is essential that you understand how to use this medication. Refer to the instructions for use that come with the medication, and if you have any questions or concerns, consult with the doctor or pharmacist.
Before administering the medication, remove it from the refrigerator and let it reach room temperature for 15 minutes. Do not heat the medication. As instructed by the doctor, mix the medication before use.
Important Administration Guidelines
Rotate the injection site with each dose to avoid tissue damage.
Do not inject the medication through clothing.
Avoid injecting into skin that is irritated, bruised, red, infected, hard, or scarred.
Wash your hands before and after handling the medication.
Do not use the medication if the solution appears cloudy, is leaking, or contains particles.
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.
* Dispose of needles and other sharp objects in a designated disposal box. Do not reuse needles or other items. When the box is full, follow local regulations for disposal. If you have any questions, consult with a doctor or pharmacist.
Storage and Disposal
Store the medication in a refrigerator at a temperature between 2°C and 8°C (36°F and 46°F). Do not freeze. 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. You may return the medication 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 you miss a dose, administer it as soon as you remember. However, if your child misses a dose by more than 2 days, skip the missed dose and resume the regular schedule. Do not administer two doses within 5 days of each other.
Lifestyle & Tips
- Maintain a balanced diet and regular exercise as recommended by your doctor.
- Ensure adequate sleep, as growth hormone is released during sleep.
- Follow proper injection technique and rotate injection sites to prevent skin problems.
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/week, administered once weekly by subcutaneous injection. Dose may be adjusted based on IGF-1 levels and growth response, up to a maximum of 0.48 mg/kg/week.
Adolescent:
Initial dose: 0.24 mg/kg/week, administered once weekly by subcutaneous injection. Dose may be adjusted based on IGF-1 levels and growth response, up to a maximum of 0.48 mg/kg/week.
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended, but caution advised.
Moderate:
No specific dose adjustment recommended, but caution advised.
Severe:
No specific dose adjustment recommended, but caution advised.
Dialysis:
No specific recommendations; use with caution and monitor closely.
Hepatic Impairment:
Mild:
No specific dose adjustment recommended, but caution advised.
Moderate:
No specific dose adjustment recommended, but caution advised.
Severe:
No specific dose adjustment recommended, but caution advised.
Pharmacology
Mechanism of Action
Lonapegsomatropin is a long-acting prodrug of somatropin. It consists of somatropin covalently bound to a methoxy polyethylene glycol (mPEG) polymer. The mPEG moiety is slowly cleaved off over time, releasing active somatropin. Somatropin (recombinant human growth hormone) binds to specific growth hormone receptors on target cells, stimulating linear growth in children with growth hormone deficiency (GHD) and affecting protein, carbohydrate, and lipid metabolism.
Pharmacokinetics
Absorption:
Bioavailability:
Not explicitly quantified as a percentage for the prodrug, but designed for sustained release and absorption from subcutaneous tissue.
Tmax:
Approximately 5 days (for released somatropin)
FoodEffect:
Not applicable (subcutaneous injection)
Distribution:
Vd:
Approximately 0.07-0.1 L/kg (for released somatropin)
ProteinBinding:
Low (for released somatropin)
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 25-40 hours (for released somatropin, significantly longer than native somatropin due to sustained release from prodrug)
Clearance:
Not precisely quantified for the prodrug; for somatropin, approximately 0.1-0.2 L/hr/kg.
ExcretionRoute:
Primarily renal (metabolites)
Unchanged:
Negligible
Pharmacodynamics
OnsetOfAction:
Gradual (due to sustained release)
PeakEffect:
Approximately 5 days (on IGF-1 levels)
DurationOfAction:
Weekly
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, this medication can cause severe and potentially life-threatening side effects. If your child experiences any of the following symptoms, contact their doctor immediately or seek emergency medical attention:
Allergic Reaction: 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, or swelling of the mouth, face, lips, tongue, or throat.
High Blood Sugar: Confusion, feeling sleepy, unusual thirst or hunger, frequent urination, flushing, rapid breathing, or fruity-smelling breath.
Pancreas Problem (Pancreatitis): Severe stomach pain, severe back pain, or severe nausea and vomiting.
Weak Adrenal Gland: Severe nausea and vomiting, severe dizziness or fainting, muscle weakness, extreme fatigue, mood changes, decreased appetite, or weight loss.
Low Thyroid Levels: Constipation, sensitivity to cold, memory problems, mood changes, or abnormal burning, numbness, or tingling sensations.
Infection: Fever, chills, severe sore throat, ear or sinus pain, cough, increased or discolored sputum, painful urination, mouth sores, or a wound that won't heal.
Skin Changes: A new lump or growth, changes in the color or size of a mole, skin breakdown at the injection site, or unexplained bruising or bleeding.
Musculoskeletal Problems: Muscle or joint pain, or burning, numbness, pain, or tingling in the hands, arms, wrists, legs, or feet.
Bone Problems: Hip or knee pain, or a limp in children (possible slipped growth plate). Severe bone problems can occur; contact the doctor if your child experiences new or worsening bone pain.
Raised Pressure in the Head: Although rare, this can occur, especially in patients with Turner syndrome or Prader-Willi syndrome. Seek medical help if your child experiences changes in vision, severe headache, nausea, or vomiting, especially within the first 8 weeks of treatment.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to monitor your child's health. If your child experiences any of the following side effects or any other symptoms that bother them or persist, contact their doctor:
Upset stomach or vomiting
Stomach pain or diarrhea
This is not an exhaustive list of possible side effects. If you have concerns or questions, consult your child's doctor for medical advice.
Although rare, this medication can cause severe and potentially life-threatening side effects. If your child experiences any of the following symptoms, contact their doctor immediately or seek emergency medical attention:
Allergic Reaction: 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, or swelling of the mouth, face, lips, tongue, or throat.
High Blood Sugar: Confusion, feeling sleepy, unusual thirst or hunger, frequent urination, flushing, rapid breathing, or fruity-smelling breath.
Pancreas Problem (Pancreatitis): Severe stomach pain, severe back pain, or severe nausea and vomiting.
Weak Adrenal Gland: Severe nausea and vomiting, severe dizziness or fainting, muscle weakness, extreme fatigue, mood changes, decreased appetite, or weight loss.
Low Thyroid Levels: Constipation, sensitivity to cold, memory problems, mood changes, or abnormal burning, numbness, or tingling sensations.
Infection: Fever, chills, severe sore throat, ear or sinus pain, cough, increased or discolored sputum, painful urination, mouth sores, or a wound that won't heal.
Skin Changes: A new lump or growth, changes in the color or size of a mole, skin breakdown at the injection site, or unexplained bruising or bleeding.
Musculoskeletal Problems: Muscle or joint pain, or burning, numbness, pain, or tingling in the hands, arms, wrists, legs, or feet.
Bone Problems: Hip or knee pain, or a limp in children (possible slipped growth plate). Severe bone problems can occur; contact the doctor if your child experiences new or worsening bone pain.
Raised Pressure in the Head: Although rare, this can occur, especially in patients with Turner syndrome or Prader-Willi syndrome. Seek medical help if your child experiences changes in vision, severe headache, nausea, or vomiting, especially within the first 8 weeks of treatment.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to monitor your child's health. If your child experiences any of the following side effects or any other symptoms that bother them or persist, contact their doctor:
Upset stomach or vomiting
Stomach pain or diarrhea
This is not an exhaustive list of possible side effects. If you have concerns or questions, consult your child's doctor for medical advice.
Seek Immediate Medical Attention If You Experience:
- Severe or persistent headache, especially with nausea, vomiting, or vision changes (could be signs of increased pressure in the brain).
- New or worsening limping, or hip/knee pain (could be a slipped hip bone).
- Changes in moles or skin lesions (report to doctor).
- Signs of an allergic reaction: rash, itching, hives, swelling of the face, lips, tongue, or throat, difficulty breathing.
- Increased thirst or urination (could be 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:
Any allergies your child may have to this medication, its components, or other substances, including foods and drugs. Please describe the allergic reaction and its symptoms.
If your child has a history of breathing problems, such as sleep apnea, or other health conditions like:
+ Cancer or tumors, including brain tumors
+ Diabetic eye disease
+ Recent illness 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:
Any allergies your child may have to this medication, its components, or other substances, including foods and drugs. Please describe the allergic reaction and its symptoms.
If your child has a history of breathing problems, such as sleep apnea, or other health conditions like:
+ Cancer or tumors, including brain tumors
+ Diabetic eye disease
+ Recent illness 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 or worsening diabetes, while taking this drug. To monitor this, follow the doctor's instructions for checking your child's blood sugar levels. Additionally, adhere to the recommended schedule for your child's blood work and eye exams as advised by their doctor.
This medication may interfere with certain laboratory tests. Be sure to notify all of your child's healthcare providers and laboratory personnel that your child is taking this drug.
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, as this can lead to the transmission of infections, including those that may not be immediately apparent.
One of the potential side effects of this medication is excessive fluid retention in the body, which can, in some cases, lead to heart failure. 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 (an abnormal curvature of the spine), discuss this with their doctor, as this medication may exacerbate the condition in children who are still growing.
For children with a history of cancer or tumors, it is crucial to consult with their doctor, as this medication may increase the risk of cancer or tumor growth. Additionally, the risk of developing new tumors may also be elevated in some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially fatal respiratory problems while taking this medication. This risk may be further increased in children who have sleep apnea, lung or airway infections, airway obstruction, or are severely overweight. If your child has 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 during sleep, contact their doctor immediately.
If your child is pregnant or breastfeeding, it is essential to discuss the benefits and risks of this medication with their doctor, as it may affect both your child and the baby.
Your child may be at risk for high blood sugar, including the development of new or worsening diabetes, while taking this drug. To monitor this, follow the doctor's instructions for checking your child's blood sugar levels. Additionally, adhere to the recommended schedule for your child's blood work and eye exams as advised by their doctor.
This medication may interfere with certain laboratory tests. Be sure to notify all of your child's healthcare providers and laboratory personnel that your child is taking this drug.
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, as this can lead to the transmission of infections, including those that may not be immediately apparent.
One of the potential side effects of this medication is excessive fluid retention in the body, which can, in some cases, lead to heart failure. 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 (an abnormal curvature of the spine), discuss this with their doctor, as this medication may exacerbate the condition in children who are still growing.
For children with a history of cancer or tumors, it is crucial to consult with their doctor, as this medication may increase the risk of cancer or tumor growth. Additionally, the risk of developing new tumors may also be elevated in some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially fatal respiratory problems while taking this medication. This risk may be further increased in children who have sleep apnea, lung or airway infections, airway obstruction, or are severely overweight. If your child has 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 during sleep, contact their doctor immediately.
If your child is pregnant or breastfeeding, it is essential to discuss the benefits and risks of this medication with their doctor, as it may affect both your child and the baby.
Overdose Information
Overdose Symptoms:
- Acute overdose: Hypoglycemia (low blood sugar) initially, followed by hyperglycemia (high blood sugar).
- Chronic overdose: Signs and symptoms of gigantism (in children) or acromegaly (in adults), including excessive growth, joint pain, carpal tunnel syndrome, and other metabolic disturbances.
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. For poison control, call 1-800-222-1222. Management is supportive, addressing hypoglycemia if present, and discontinuing the drug in chronic overdose.
Drug Interactions
Major Interactions
- Glucocorticoids (may inhibit growth-promoting effects)
- Insulin and/or other antidiabetic agents (may require dose adjustment due to potential for hyperglycemia)
Moderate Interactions
- Thyroid hormones (may alter growth hormone response)
- CYP450-metabolized drugs (e.g., corticosteroids, sex steroids, cyclosporine, anticonvulsants - somatropin can induce CYP3A4)
Confidence Interactions
Monitoring
Baseline Monitoring
IGF-1 levels
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy
Thyroid function (TSH, free T4)
Rationale: Hypothyroidism can interfere with growth response; treat before or during therapy.
Timing: Prior to initiation of therapy
Glucose and HbA1c
Rationale: To assess baseline glucose metabolism; growth hormone can affect glucose tolerance.
Timing: Prior to initiation of therapy
Bone age
Rationale: To assess skeletal maturity and growth potential.
Timing: Prior to initiation of therapy
Fundoscopic examination
Rationale: To rule out papilledema (sign of intracranial hypertension).
Timing: Prior to initiation of therapy
Height and Weight
Rationale: To establish baseline growth parameters.
Timing: Prior to initiation of therapy
Routine Monitoring
IGF-1 levels
Frequency: Every 3-6 months, or as clinically indicated
Target: Within age- and sex-appropriate reference range
Action Threshold: Levels consistently above or below target range; adjust dose accordingly.
Growth velocity (height and weight)
Frequency: Every 3-6 months
Target: Appropriate for age and GHD treatment
Action Threshold: Suboptimal growth velocity despite adequate IGF-1 levels may indicate need for further evaluation.
Thyroid function (TSH, free T4)
Frequency: Every 6-12 months, or as clinically indicated
Target: Normal
Action Threshold: Abnormal levels require treatment of hypothyroidism.
Glucose and HbA1c
Frequency: Annually, or as clinically indicated
Target: Normal
Action Threshold: Elevated levels may require dose adjustment or antidiabetic therapy.
Fundoscopic examination
Frequency: Periodically, or if symptoms of intracranial hypertension occur
Target: No papilledema
Action Threshold: Presence of papilledema requires discontinuation and evaluation.
Symptom Monitoring
- Persistent severe headache
- Visual changes (e.g., blurred vision, double vision)
- Nausea and/or vomiting (signs of benign intracranial hypertension)
- Limping or hip/knee pain (signs of slipped capital femoral epiphysis)
- Progression of scoliosis
- Changes in nevi or skin lesions (potential for malignancy)
- Signs of allergic reaction (rash, itching, swelling, difficulty breathing)
- Injection site reactions (pain, redness, swelling)
Special Patient Groups
Pregnancy
Risk summary: Insufficient data on lonapegsomatropin use in pregnant women to inform a drug-associated risk for major birth defects or miscarriage. Animal reproduction studies have not been conducted with lonapegsomatropin. Use only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Risk unknown; insufficient data.
Second Trimester:
Risk unknown; insufficient data.
Third Trimester:
Risk unknown; insufficient data.
Lactation
Risk summary: It is not known whether lonapegsomatropin is excreted 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. Caution should be exercised when Skytrofa is administered to a nursing mother.
Infant Risk:
Risk unknown; insufficient 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 use in geriatric patients. Growth hormone deficiency in adults is typically treated with daily somatropin formulations.
Clinical Information
Clinical Pearls
- Skytrofa offers a significant advantage of once-weekly subcutaneous administration, which can improve adherence compared to daily growth hormone injections.
- Dosing is weight-based and adjusted according to IGF-1 levels and growth response. Careful monitoring of IGF-1 is crucial to ensure efficacy and minimize potential side effects.
- Patients and caregivers must be thoroughly trained on proper subcutaneous injection technique and rotation of injection sites.
- Patients should be monitored for signs of benign intracranial hypertension (e.g., severe headache, visual changes) and slipped capital femoral epiphysis (e.g., limping, hip/knee pain).
Alternative Therapies
- Other somatropin (recombinant human growth hormone) products (e.g., Norditropin, Genotropin, Humatrope, Nutropin, Saizen, Omnitrope, Zomacton) - typically administered daily.
- Somapacitan (Sogroya) - another long-acting growth hormone, currently approved for adult GHD, not pediatric GHD.
Cost & Coverage
Average Cost:
Highly variable, typically several thousand dollars per month per cartridge
Insurance Coverage:
Specialty Tier (requires prior authorization, often subject to strict criteria)
General Drug Facts
If your child's symptoms or health issues persist or worsen, it's 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 come with an additional patient information leaflet; if you have 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 urgent medical attention. When reporting the incident, be prepared to provide detailed information, including the substance taken, the amount, and the time it occurred.