Skytrofa 11mg Inj Cartridge
It is used to help with growth and to treat growth hormone deficiency.
Drug Class
Growth Hormone
Pharmacologic Class
Somatropin (Growth Hormone) Analog
Pregnancy Category
Not available
FDA Approved
Aug 2021
DEA Schedule
Not Controlled
Overview
What is this medicine?
Skytrofa is a medicine given by injection once a week to help children with growth hormone deficiency grow taller. It works by providing a long-acting form of the natural growth hormone that their bodies are not making enough of.
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 to understand how to use this medication correctly. 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 using 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, following the provided guidelines.
When administering the injection, rotate the injection site with each dose to avoid tissue damage. Avoid injecting through clothing, and do not inject into skin that is irritated, bruised, red, infected, hard, or scarred. Wash your hands before and after handling the medication.
Important Safety Precautions
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.
Proper Disposal
Dispose of needles and other sharp objects in a designated needle/sharp disposal box. Do not reuse needles or other items. When the box is full, follow local regulations for disposal. If you have any questions or concerns, consult with a doctor or pharmacist.
Storage and Handling
Store the medication in the refrigerator, but 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, 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 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 to understand how to use this medication correctly. 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 using 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, following the provided guidelines.
When administering the injection, rotate the injection site with each dose to avoid tissue damage. Avoid injecting through clothing, and do not inject into skin that is irritated, bruised, red, infected, hard, or scarred. Wash your hands before and after handling the medication.
Important Safety Precautions
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.
Proper Disposal
Dispose of needles and other sharp objects in a designated needle/sharp disposal box. Do not reuse needles or other items. When the box is full, follow local regulations for disposal. If you have any questions or concerns, consult with a doctor or pharmacist.
Storage and Handling
Store the medication in the refrigerator, but 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, 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 regular schedule. Do not administer two doses within 5 days of each other.
Lifestyle & Tips
- Administer the injection 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 cartridges in the refrigerator (2°C to 8°C / 36°F to 46°F). Do not freeze.
- Discard cartridges after 28 days of first use or if expired.
- Follow up regularly with the healthcare provider for monitoring of growth, blood tests, and overall health.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Not indicated for adult growth hormone deficiency.
Pediatric Dosing
Neonatal:
Not established (approved for patients 1 year and older)
Infant:
Initial: 0.16 mg/kg once weekly. May increase by 0.04 mg/kg/week every 4 to 8 weeks, up to a maximum of 0.24 mg/kg/week. (For patients 1 year and older)
Child:
Initial: 0.16 mg/kg once weekly. May increase by 0.04 mg/kg/week every 4 to 8 weeks, up to a maximum of 0.24 mg/kg/week.
Adolescent:
Initial: 0.16 mg/kg once weekly. May increase by 0.04 mg/kg/week every 4 to 8 weeks, up to a maximum of 0.24 mg/kg/week.
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended.
Moderate:
No specific dose adjustment recommended.
Severe:
No specific dose adjustment recommended.
Dialysis:
Not available
Hepatic Impairment:
Mild:
No specific dose adjustment recommended.
Moderate:
No specific dose adjustment recommended.
Severe:
No specific dose adjustment recommended.
Pharmacology
Mechanism of Action
Lonapegsomatropin is a long-acting prodrug of somatropin. It is a covalent conjugate of somatropin with a methoxy-polyethylene glycol (PEG) polymer. Following subcutaneous injection, lonapegsomatropin is slowly cleaved to release somatropin. Somatropin binds to specific growth hormone (GH) receptors on target cells, stimulating linear growth and protein, carbohydrate, and lipid metabolism.
Pharmacokinetics
Absorption:
Bioavailability:
Not explicitly quantified for lonapegsomatropin, but designed for sustained release.
Tmax:
Somatropin Tmax from lonapegsomatropin: Approximately 8 days (range 3-14 days)
FoodEffect:
Not applicable (subcutaneous injection)
Distribution:
Vd:
Somatropin Vd: Approximately 0.07 L/kg
ProteinBinding:
Somatropin: High (to growth hormone binding protein, GHBP)
CnssPenetration:
Limited
Elimination:
HalfLife:
Somatropin half-life from lonapegsomatropin: Approximately 25-48 hours
Clearance:
Not available
ExcretionRoute:
Renal (somatropin metabolites)
Unchanged:
Not available
Pharmacodynamics
OnsetOfAction:
Not acutely defined; sustained effect over weekly dosing interval.
PeakEffect:
Not acutely defined; sustained effect over weekly dosing interval.
DurationOfAction:
Approximately 7 days (allowing for once-weekly dosing)
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 or seek medical attention immediately:
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, fast 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; seek medical help if your child experiences new or worsening bone pain.
Raised Pressure in the Head: Although rare, this can occur, especially in children 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
Most people experience no side effects or only mild ones. However, if your child experiences any of the following side effects, contact their doctor or seek medical attention if they are bothersome or persistent:
Upset stomach or vomiting
Stomach pain or diarrhea
This is not an exhaustive list of possible side effects. If you have concerns about side effects, 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 or seek medical attention immediately:
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, fast 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; seek medical help if your child experiences new or worsening bone pain.
Raised Pressure in the Head: Although rare, this can occur, especially in children 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
Most people experience no side effects or only mild ones. However, if your child experiences any of the following side effects, contact their doctor or seek medical attention if they are bothersome or persistent:
Upset stomach or vomiting
Stomach pain or diarrhea
This is not an exhaustive list of possible side effects. If you have concerns about side effects, 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 (signs of intracranial hypertension)
- New or worsening limping, or hip/knee pain (slipped capital femoral epiphysis)
- Progression of pre-existing scoliosis
- Changes in skin lesions or moles (potential for malignancy)
- Signs of an allergic reaction (rash, hives, swelling of face/lips/tongue, difficulty breathing)
- Signs of high blood sugar (increased thirst, increased urination, fatigue)
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 certain health conditions, such as:
+ Breathing problems, including sleep apnea
+ Cancer or other 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 certain health conditions, such as:
+ Breathing problems, including sleep apnea
+ Cancer or other 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-onset diabetes or worsening of existing diabetes. Regularly check your child's blood sugar levels as instructed by their doctor. Additionally, follow the doctor's recommendations for blood work and eye exams to monitor your child's health.
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 worsen 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 chance of cancer or tumor growth. Additionally, the risk of new tumors may be elevated in some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially life-threatening respiratory problems, particularly if they have sleep apnea, lung or airway infections, airway obstruction, or are severely overweight. If your child experiences 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, 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. Regularly check your child's blood sugar levels as instructed by their doctor. Additionally, follow the doctor's recommendations for blood work and eye exams to monitor your child's health.
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 worsen 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 chance of cancer or tumor growth. Additionally, the risk of new tumors may be elevated in some patients.
Children with Prader-Willi syndrome are at a higher risk for severe and potentially life-threatening respiratory problems, particularly if they have sleep apnea, lung or airway infections, airway obstruction, or are severely overweight. If your child experiences 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, consult with their doctor to discuss the potential benefits and risks to both your child and the baby.
Overdose Information
Overdose Symptoms:
- Acute overdose: Initial hypoglycemia followed by hyperglycemia.
- Chronic overdose: Signs and symptoms of gigantism and/or acromegaly (e.g., excessive growth, enlarged hands/feet, joint pain, carpal tunnel syndrome).
What to Do:
Acute overdose: Manage hypoglycemia if severe. Chronic overdose: Discontinue Skytrofa and evaluate for complications. Call 911 or Poison Control (1-800-222-1222) for immediate assistance.
Drug Interactions
Moderate Interactions
- Glucocorticoids
- Thyroid hormones
- Insulin and/or other antidiabetic agents
- Oral Estrogen
Monitoring
Baseline Monitoring
IGF-1 and IGFBP-3 levels
Rationale: To confirm GHD diagnosis and establish baseline for treatment monitoring.
Timing: Prior to initiation of therapy
Thyroid function tests (TSH, Free T4)
Rationale: To rule out hypothyroidism, which can interfere with growth response.
Timing: Prior to initiation of therapy
Fasting glucose and HbA1c
Rationale: To assess glucose metabolism and screen for diabetes.
Timing: Prior to initiation of therapy
Bone age
Rationale: To assess skeletal maturity in pediatric patients.
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 4-8 weeks during dose titration, then every 3-6 months once stable.
Target: Age- and sex-adjusted normal range (0 to +2 SDS)
Action Threshold: If IGF-1 SDS is consistently above +2, consider dose reduction. If below target, consider dose increase.
Height and weight
Frequency: Every 3-6 months
Target: Improved growth velocity
Action Threshold: Lack of adequate growth response may indicate need for dose adjustment or re-evaluation of diagnosis.
Thyroid function tests
Frequency: Every 6-12 months, or if clinical signs of hypothyroidism develop.
Target: Normal range
Action Threshold: Treat hypothyroidism if present.
Fasting glucose and HbA1c
Frequency: Annually, or if clinical signs of glucose intolerance develop.
Target: Normal range
Action Threshold: Manage hyperglycemia if present.
Fundoscopic examination
Frequency: Periodically, or if symptoms of intracranial hypertension occur.
Target: No papilledema
Action Threshold: Discontinue therapy if papilledema is confirmed.
Scoliosis assessment
Frequency: Regularly during periods of rapid growth.
Target: No progression
Action Threshold: Refer to orthopedist if scoliosis progresses.
Symptom Monitoring
- Persistent severe headache
- Visual changes (e.g., blurred vision, double vision)
- Nausea or vomiting
- Limping or hip/knee pain (slipped capital femoral epiphysis)
- New or worsening scoliosis
- Changes in skin lesions (e.g., moles)
- Signs of allergic reaction (rash, itching, swelling, difficulty breathing)
- Signs of injection site reactions (pain, redness, swelling)
Special Patient Groups
Pregnancy
There are no adequate and well-controlled studies of lonapegsomatropin in pregnant women. Animal studies have shown adverse developmental effects at doses higher than clinical exposure. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Not specifically studied, but general caution with growth hormones.
Second Trimester:
Not specifically studied.
Third Trimester:
Not specifically studied.
Lactation
It is unknown whether lonapegsomatropin is excreted in human milk. Somatropin is excreted in human milk. Consider the developmental and health benefits of breastfeeding 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; potential for adverse effects on infant growth or metabolism.
Pediatric Use
Skytrofa is indicated for the treatment of pediatric patients 1 year and older with growth hormone deficiency. Safety and effectiveness in pediatric patients younger than 1 year have not been established.
Geriatric Use
Not indicated for geriatric patients. Safety and efficacy have not been established in patients over 65 years of age.
Clinical Information
Clinical Pearls
- Skytrofa offers a once-weekly dosing regimen, which can improve adherence compared to daily growth hormone injections.
- Careful monitoring of IGF-1 levels is crucial for dose titration to ensure efficacy and minimize adverse effects.
- Patients and caregivers must be trained on proper subcutaneous injection technique and site rotation.
- Monitor for signs and symptoms of intracranial hypertension (e.g., severe headache, visual changes) and slipped capital femoral epiphysis (e.g., limping, hip/knee pain), especially during periods of rapid growth.
- Hypothyroidism can reduce the response to growth hormone therapy; ensure thyroid function is optimized.
- Growth hormone therapy may induce a state of insulin resistance; monitor glucose levels, especially in patients with risk factors for diabetes.
Alternative Therapies
- Somatropin (daily injections, e.g., Genotropin, Humatrope, Norditropin, Nutropin, Saizen, Zomacton)
- Somapacitan (Sogroya - once-weekly growth hormone, approved for adult GHD, but also pediatric GHD in some regions)
Cost & Coverage
Average Cost:
High (typically several thousand USD) per 11mg 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 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 come with 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 details about the medication taken, the quantity, and the time it occurred.