Increlex
Increlex (mecasermin) is a recombinant insulin-like growth factor-1 (IGF-1). It treats children 2 years and older who are short for their age as a result of certain genetic conditions. These children have either severe primary IGF-1 deficiency or growth hormone (GH) deletion with antibodies that attack GH. Increlex (mecasermin) is given as an injection under the skin twice a day. Dosing is based on how much your child weighs, how well the medication is working, and whether there are side effects. Side effects can include headache and bruising at the injection site. It can also put your child at risk for low blood sugar (hypoglycemia).
What is Increlex (mecasermin)?
What is Increlex (mecasermin) used for?
Improving growth in children who are very short for their age because of severe primary IGF-1 deficiency or growth hormone (GH) deletion and have developed antibodies that attack GH
How Increlex (mecasermin) works
Increlex (mecasermin) is a recombinant insulin-like growth factor-1 (IGF-1). It's a lab-made version of the natural hormone your body makes called IGF-1. This hormone is important for your bones and tissues to grow properly.
Children with primary IGF-1 deficiency or GH gene deletion have very low levels of IGF-1. Because they don't have enough IGF-1 in the body, these children can't grow properly. Increlex (mecasermin) helps raise their IGF-1 levels so that their growth can improve.
Drug Facts
What are the side effects of Increlex (mecasermin)?
Common Side Effects
- Low blood sugar (42%)
- Swollen tonsils (15%)
- Bruising where the medication is injected
- Thickening of skin where the medication is injected
- Headache
- Dizziness
- Uncontrolled muscle spasms
- Vomiting
- Joint pain
- Pain in the arm or leg
- Ear infection
- Ear pain
- Fluid buildup in the ear
- Snoring
Other Side Effects
- Thickening of skin around the face
- Other reaction where the medication is injected (e.g., irritation, redness, pain, rash)
Serious Side Effects
- Dangerously low blood sugar: feeling faint, shaking, sweating, dizziness, fast heartbeat, nervousness, anxious, confused, irritable, feeling very hungry
- Serious allergic reaction: hives, rash, itching, dizziness, shaking, flushing, nausea, trouble breathing, chest pain, swelling of the face or mouth
- High pressure in the brain: changes in vision, headache, nausea, vomiting
Source: DailyMed
The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
bluish skin color of the fingertips
blurred vision
breathlessness
chills
cold sweats
coma
confusion
cool, pale skin
dizziness
fast heartbeat
headache
increased hunger
loss of hearing
nervousness
nightmares
rapid growth of normal cells of the thymus (no symptoms)
seizures
shakiness
slurred speech
thickening of the skin
unusual tiredness or weakness
Incidence not known
Change in the ability to see colors, especially blue or yellow
difficult or labored breathing
difficulty with swallowing
hives or welts, itching, or skin rash
itching or hives at the injection site
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
limp
pain in the hip or knee
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
redness of the skin
tightness in the chest
vomiting
Get emergency help immediately if any of the following symptoms of overdose occur:
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Abnormal response of the tympanic membrane to air pressure
difficulty with moving
difficulty with swallowing
ear pain
large, flat, blue or purplish patches in the skin
muffled hearing
muscle pain or stiffness
redness or swelling in the ear
sense of fullness in the ear
snoring
voice changing
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Increlex (mecasermin)
Pros
Works well to promote growth in children with certain genetic conditions
Can give injection at home
Cons
Needs to be given as an injection under the skin twice per day
Need to eat food within 20 minutes of the injection
Pharmacist tips for Increlex (mecasermin)
Mark your child's appointments on your calendar so they get followed up and examined on time. This makes sure your child is properly monitored while they're taking Increlex (mecasermin).
Make sure your child can eat something within 20 minutes either before or after Increlex (mecasermin) gets injected. If they can't eat anything within this time, skip the injection. This is important because Increlex (mecasermin) has a similar effect to insulin and lowers blood sugar. Having food in the stomach around the time of the injection helps prevent the blood sugar from dropping too low.
Children should avoid high-risk activities (like exercising and driving) within 2 to 3 hours after each Increlex (mecasermin) injection. This is important because exercise can lower blood sugar levels. This helps prevent your child from getting hurt if they have symptoms of low blood sugar, like shakiness, confusion, or passing out.
Know how to spot when your child has low blood sugar and how to treat low blood sugar if it happens. Look out for symptoms such as feeling faint, shaking, and sweating. Make sure you have some glucose tablets, hard candies, or juice with sugar handy so you can use them to get blood sugar back up fast. Call 911 if their symptoms don't improve.
Tips on how to use Increlex (mecasermin):
The care team will show you how to draw up the dose into a syringe and inject Increlex (mecasermin). Be sure to review the instructions before each injection. Ask the care team if you're not sure how to use the medication.
Store new, unopened vials of Increlex (mecasermin) in the refrigerator away from light. After using the vial for the first time, place it in the refrigerator for up to 30 days. Write the 30-day expiration date on the vial after you've opened (used) it for the first time.
Increlex (mecasermin) comes in vials that contain enough medication for more than one dose. This means that you use the same vial until it runs out of medication or until the vial's been open for 30 days. Throw away the vial after 30 days, even if there's still medication inside.
Always check to make sure the medication in the vial is clear and colorless before using it. Don't use it if it's cloudy, discolored, or has particles (solid chunks). Ask your child's prescriber or pharmacist about what to do next.
Always use a new needle and syringe for each Increlex (mecasermin) injection. This helps prevent infections and blocked needles. Don't reuse or share needles with other people to avoid spreading infections.
After you've drawn up the dose into a syringe, clean the area where you'll inject the medication with an alcohol swab. Then, inject Increlex (mecasermin) under the skin into the fatty tissue of the upper arm, thigh, buttock, or stomach. Choose a different place to inject that's different from the last to avoid skin irritation.
Right after the injection, throw away used syringes and needles into a sharps container or something made of heavy-duty plastic (e.g., empty milk carton, laundry detergent bottle). This lowers the risk of needle-stick injuries. Don't throw them away in your trash can. Learn more about how to throw away sharps on the FDA's website.
More on Increlex (mecasermin) tips
Frequently asked questions about Increlex (mecasermin)
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What are the risks and warnings for Increlex (mecasermin)?
Increlex (mecasermin) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Low blood sugar (hypoglycemia)
Risk factors: Younger-aged children | Changes in diet or exercise | Taking other medications that lower blood sugar | Change in dose of Increlex (mecasermin) | Taking more Increlex (mecasermin) than prescribed | Not eating within 20 minutes of taking Increlex (mecasermin) | High-risk activities within 2 to 3 hours of taking Increlex (mecasermin)
Increlex (mecasermin) can cause dangerously low blood sugar (hypoglycemia), which can be life-threatening. Low blood sugar is more likely to happen when your child is just starting Increlex (mecasermin) and when the dose is changing a lot to reach a stable dose.
To lower the risk for hypoglycemia, your child must eat a meal or snack 20 minutes before or 20 minutes after they get their Increlex (mecasermin) injection. If they can't eat within this time frame, then they should skip the dose. Pay close attention for young children because they might not eat as consistently as older children.
Children should avoid high-risk activities (like exercising and driving) within 2 to 3 hours after the injection. This helps prevent accidents or injuries from happening if they have symptoms of low blood sugar, including shakiness, sweating, confusion, or passing out.
Make sure you and your child, if old enough, know how to recognize and treat low blood sugar before treatment starts. It's best to always have some form of fast-acting sugar (e.g., glucose tablets, hard candy, fruit juice) with you during treatment. This is helpful when you need to get the blood sugar up fast if it becomes too low. Call 911 right away if your child's blood sugar continues to be low.
Allergic reaction
It's possible to have an allergic reaction to Increlex (mecasermin). These reactions can include widespread hives, swelling of the face or mouth, trouble breathing, and anaphylaxis. Get medical help right away if an allergic reaction to Increlex (mecasermin) happens.
High pressure in the brain
Some children who took Increlex (mecasermin) have developed high pressure in the brain. High pressure in the brain can lead to changes in vision, headache, nausea, and vomiting. It can also lead to an eye problem called papilledema (swelling in the eye).
Your child will need to get their eyes checked for papilledema before they start taking Increlex (mecasermin) and also throughout treatment. Tell your child's care team right away if your child has any signs or symptoms of high pressure in the brain, such as blurry vision, changes in vision, headache every day, or nausea, while they're taking this medication.
Lymph tissues (tonsils and adenoids) that grow too big
During treatment with Increlex (mecasermin), some children had tonsils and adenoids, which are part of the immune system, that grew too big. This has caused problems with sleeping, such as sleep apnea and snoring. It's also sometimes caused fluid buildup in the ear. During follow-up visits, the care team will check your child's tonsils and adenoids to make sure they're a normal size.
Hip problems
Since Increlex (mecasermin) stimulates growth in children, it can cause a hip problem known as slipped capital femoral epiphysis. This happens when the thigh bone slips out of the socket. It can happen in children who are growing very fast. Contact your child's prescriber if your child has a limp or complains of hip or knee pain during treatment with Increlex (mecasermin). These can be signs of hip problems.
Worsening curving of the spine (scoliosis)
Risk factors: Scoliosis
If your child has scoliosis, Increlex (mecasermin) can make it worse because the medication makes them grow faster. Your child's care team will check for signs that the scoliosis is getting worse at follow-up visits. These signs can include an uneven waist or shoulders or the body leaning to one side.
Risk of cancer
Risk factors: Taking Increlex (mecasermin) at higher-than-recommended doses | Taking Increlex (mecasermin) at doses that produced too much IGF-1 | Other medical conditions that raise the risk for cancer
Some children who took Increlex (mecasermin) have developed cancer. But it's not clear whether Increlex (mecasermin) caused the cancer. Many of these children also had other risk factors for cancer or took Increlex (mecasermin) at higher-than-recommended doses. Your child can't take Increlex (mecasermin) if they have cancer now or had it in the past because of this risk. Talk to your child's prescriber if you're worried about this risk. Ask them about your child's risk for cancer.
Increlex (mecasermin) dosage forms
Typical dosing for Increlex (mecasermin)
Increlex (mecasermin) is given as an injection under the skin either in the upper arm, thigh, buttock, or stomach. Only give the injection if your child can eat a meal or snack 20 minutes before or 20 minutes after the shot.
The dose is based on your child's weight. The typical starting dose is 0.04 mg/kg to 0.08 mg/kg injected under the skin twice a day. Your child's prescriber might slowly raise the dose up to a maximum of 0.12 mg/kg twice a day as long as there aren't side effects.
Interactions between Increlex (mecasermin) and other drugs
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Increlex (mecasermin) contraindications
Closed growth plate (when cartilage at the end of a long bone hardens into bone; a sign that the bone is done growing)
Currently have or have had cancer
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References
Best studies we foundAmerican Diabetes Association. (n.d.). Blood glucose and exercise.
Anderson, L. J., et al. (2018). Use of growth hormone, IGF-I, and insulin for anabolic purpose: Pharmacological basis, methods of detection, and adverse effects. Molecular and Cellular Endocrinology.
Chen, J. J. (2024). Papilledema. Merck Manual Consumer Version.
Child Growth Foundation. (n.d.). Primary IGF-1 deficiency.
Cogan, J. D., et al. (2006). GH1 gene deletions and IGHD type 1A. Pediatric Endocrinology Reviews.
ENThealth. (2019). Tonsils and adenoids. American Academy of Otolaryngology-Head and Neck Surgery Foundation.
Ipsen Biopharmaceuticals, Inc. (2019). Patient information: Increlex® (EENK-RUH-LEX) (mecasermin) injection for subcutaneous use.
Ipsen Biopharmaceuticals, Inc. (2024). Increlex- mecasermin injection, solution [package insert]. DailyMed.
MedlinePlus. (2024). IGF-1 (insulin-like growth factor 1) test.
National Cancer Institute. (2024). Cancer in children and adolescents.
National Eye Institute. (2024). Idiopathic intracranial hypertension.
National Organization for Rare Disorders. (2016). Growth hormone deficiency.
Nemours KidsHealth. (2019). Growth plates.
OrthoInfo. (2020). Slipped capital femoral epiphysis.
Silberstein, S. D. (2025). Idiopathic intracranial hypertension. Merck Manual Consumer Version.
U.S. Food and Drug Administration. (2021). Safely using sharps (needles and syringes) at home, at work and on travel.
You and Your Hormones. (2021). Insulin.
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