Mecasermin (Subcutaneous)

Prescribed on a long-term basis, Mecasermin is used to treat growth failure in pediatric patients with severe primary IGF-I deficiency.


Insulin-like growth factor I (IGF-I), is a protein which is vital to normal growth throughout childhood. Although IGF-I has anabolic effects in older patients, its effects are far more pronounced in children, particularly when they go through puberty.

As a mediator of the impact of growth hormone, IGF-I induces systemic body growth and affects the growth of almost every cell in the body. If patients are deficient in IGF-I, they could develop a range of health complications, such as Laron dwarfism and acromegaly.

When a severe primary IGF-I deficiency is present, patients are normally diagnosed with Laron syndrome. Characterized by normal or high growth hormone levels, height which is below three standard deviations and levels of IGF-I which are at lower than three standard deviations, this deficiency results in growth impairment.

Mecasermin is a recombinant form of IGF-I and is used to treat patients with a severe primary IGF-I deficiency. When administered to the patient, Mecasermin binds to the IGF-I receptor, which then instigates various growth processes. As a result, the patient's organs, muscles, bones and cartilage tissues can begin to develop as they should.

Although Mecasermin is effective in treating primary IGF-I deficiencies and can also be used if growth hormone gene deletion has taken place, it is not typically used to treat secondary IGF-I deficiencies.

Administered via subcutaneous injection, Mecasermin is typically used on a long-term basis and patients will generally need to continue with treatment throughout their childhood. As the patient's body does not produce normal levels of IGF-I naturally, Mecasermin is used to supplement or replace their natural production of IGF-I and to prevent the symptoms of a deficiency from occurring.

Conditions Treated

  • Primary insulin-like growth factor I (IGF-I) deficiency

Type Of Medicine

  • Recombinant human insulin-like growth factor I (rhlGF-I)
  • Protein based therapy
  • Hormone

Side Effects

Like most medications, Mecasermin can cause patients to experience some side effects, particularly when it is first used. As the patient's body becomes accustomed to the medication, side effects will often diminish. When patients first start treatment with Mecasermin, for example, they may develop the following side effects:

  • Abnormal response of the tympanic membrane to air pressure
  • Sore or painful throat
  • Difficulty with moving
  • Changes to the voice
  • Snoring
  • Difficulty with swallowing
  • Sense of fullness in the ear
  • Ear pain
  • Muffled hearing
  • Earache
  • Large, flat, purplish or blue patches in the skin
  • Pain or stiffness in the muscles
  • Swelling or redness in the ear

Although the above side effects may not require additional treatment if they are fairly mild, patients should obtain medical help if the side effects are troublesome or if they do not diminish over time.

Furthermore, patients should notify a healthcare professional immediately if they develop the following side effects when using Mecasermin:

  • Anxiety
  • Slurred speech
  • Bluish skin color of the fingertips
  • Shakiness
  • Blurred vision
  • Seizures
  • Breathlessness
  • Rapid growth of normal cells of the thymus (this may not present with any symptoms)
  • Chest pain
  • Nightmares
  • Chills
  • Nervousness
  • Cold sweats
  • Nausea
  • Coma
  • Loss or hearing
  • Confusion
  • Increased hunger
  • Pale, cool skin
  • Depression
  • Headache
  • Dizziness
  • Cough
  • Fast heartbeat
  • Thickening of the skin
  • Wheezing
  • Labored or difficult breathing
  • Vomiting
  • Change in the patient's ability to see colors, especially yellow or blue
  • Unusual weakness or tiredness
  • Difficulty with swallowing
  • Welts or hives
  • Pain in the knee or hip
  • Itching of the skin
  • Shortness of breath
  • Hives or itching at the injection site
  • Tightness in the chest
  • Rash on the skin
  • Large, hive-like swelling on the lips, throat, face, hands, eyelids, tongue, feet, legs or sex organs
  • Redness of the skin
  • Limp
  • Swelling or puffiness around the lips, tongue, face, eyes or of the eyelids

If Mecasermin is administered too often or if too much medication is used, patients could suffer an overdose. This is a medical emergency and the patient will require urgent medical treatment. If patients experience an overdose of Mecasermin, they may exhibit the following symptoms:

  • Anxiety
  • Leg or arm pain
  • Joint pain
  • Backache
  • Increased thirst
  • Changes in vision
  • Increased volume of dilute, pale urine
  • Excessive sweating
  • Increase in size of feet and/or hands
  • Extreme weakness
  • Stop in menstruation
  • Frequent urination

However, if patients or their caregivers are aware that too much Mecasermin has been used, they should seek medical help immediately and should not wait for the symptoms of an overdose to become apparent.


A patient's dose of Mecasermin is usually dependent on their weight, as well as their age and medical history. For patients who are over the age of two years, a standard dose of Mecasermin is 0.04-0.08mg per kilogram of bodyweight, twice per day. However, this dose can be increased by a physician, if it is deemed necessary. If children under the age of two years are prescribed Mecasermin, their dose will be calculated by their physician.

Although Mecasermin is administered via a subcutaneous injection, the patient's parents, guardians or caregivers may be taught how to inject the medicine at home. This prevents the patient from having to attend medical appointments on a twice daily basis. Before using the medicine, parents or caregivers will be taught how to prepare and administer Mecasermin and will be given the opportunity to practice injecting it.

When delivering the medication, a new syringe and needle must be used for every dose. If the Mecasermin solution contains particles or appears cloudy, it should not be used. If necessary, patients should obtain additional medication and should not administer Mecasermin if it is not fit for use.

Generally, Mecasermin can be injected into the abdomen, buttocks, thighs or upper arms but doctors will advise parents and caregivers where to administer the medication. Often, they will be advised to use a different injection site for each dose of Mecasermin and to rotate the injection sites which are used. This can help to prevent skin irritation occurring.

In most cases, Mecasermin should be injected 20 minutes before or 20 minutes after a meal or a snack. Once the medication has been administered, parents and caregivers must not let the patient skip the subsequent meal or snack.

In order to be effective, Mecasermin should be administered regularly and in accordance with the doctor's instructions. However, if a dose of Mecasermin is missed, it should be injected as soon as the patient's parent or caregiver remembers to do so. If the patient's next dose of Mecasermin is due relatively soon, the missed dose will need to be skipped and treatment should continue as normal. Extra doses or double doses of Mecasermin should not be administered, even if an earlier dose has been missed.

If the patient's parents, guardians or caregivers are unsure how to proceed after a missed dose or if they are unsure how to administer the medication, they should contact the patient's physician or pharmacist for advice.

Potential Drug Interactions

Due to the risk of a drug interaction occurring, Mecasermin may not be suitable for use in conjunction with certain other medications. Before Mecasermin is administered, parents or caregivers should inform the relevant healthcare practitioner if the patient is taking or using any other medicines, supplements or vitamins.

Once treatment with Mecasermin has commenced, medical advice should be sought before the patient is given any new medicines, vitamins or supplements.


If the patient has any other health problems, it's essential that their doctor is notified before Mecasermin is prescribed. There are conditions which can affect the use of Mecasermin and these may include:

  • Diabetes
  • Underactive thyroid (Hypothyroidism)
  • Closed epiphyses
  • Head injury
  • Enlarged tonsils
  • Neoplasia
  • Nutritional deficiencies
  • Scoliosis

Although pediatric patients are treated with Mecasermin, there have not been specific studies into the effects of this medication on patients under the age of two years. Although infants under this age are often treated with Mecasermin, caution must be exercised.

When patients are treated with Mecasermin, they may develop low blood sugar levels (hypoglycemia). The symptoms of low blood sugar may include:

  • Pale, cool skin
  • Blurred vision
  • Anxiety
  • Dizziness
  • Chills
  • Fast heartbeat
  • Depression
  • Cold sweats
  • Nightmares
  • Confusion
  • Nervousness
  • Coma
  • Headache
  • Slurred speech
  • Nausea
  • Shakiness
  • Increased hunger
  • Seizures
  • Unusual weakness or tiredness

If patients exhibit these symptoms, they should consume a source of sugar, such as a non-diet soft drink, fruit juice, glucose gel or tablets, candy or milk. If symptoms persist, urgent medical treatment may be required. Parents, guardians and caregivers should learn to recognize the signs of low blood sugar in the patient so that they can react quickly. In addition to this, teachers, family members and babysitters should be taught how to react to episodes of hypoglycemia and taught to recognize when medical help is required.

Patients should not engage in high risk activities within two to three hours of Mecasermin being administered. For example, adult patients should not drive within this timeframe.

Mecasermin can cause enlargement of the tonsils and the patient's mouth and throat may need to be checked at regular intervals. If the patient exhibits any of the following symptoms, their physician should be consulted:

  • Swollen tonsils
  • Fluid in the ear
  • Trouble swallowing or breathing
  • Snoring

Taking Mecasermin can increase the risk of dislocation of the hip bone. If the patient has pain in the leg, knee or hip or is walking with a limp, medical treatment must be sought.

Mecasermin contains Benzyl Alcohol which has been associated with serious side effects in premature or newborn infants. The patient's parents, guardians or caregivers should be made aware of this risk before Mecasermin is used.

When patients are taking Mecasermin, they will need to attend regular consultations with their physician. If the patient, their parent, guardian or caregiver feels that Mecasermin is causing excessive growth, they should consult their doctor straight away.

Although Mecasermin is predominately used to treat children, patients should be aware that it could cause harm to an unborn fetus if it was administered to a pregnant patient. If adult or teenage females are treated with Mecasermin, they must notify their doctor immediately if they become pregnant.

As the effects of Mecasermin on breast milk are unknown, patients should not breastfeed whilst they are being treated with Mecasermin.

Before using Mecasermin, doctors should be told if the patient has any known allergies. This includes allergies to medicines, foods, animals, preservatives, chemicals, dyes or any other substances. In rare cases, Mecasermin can cause patients to develop a serious allergic reaction, which may include anaphylaxis. The symptoms of this type of reaction can include:

  • Rash on the skin
  • Trouble breathing
  • Itching
  • Hoarseness
  • Difficulty swallowing
  • Hives
  • Swelling, affecting the mouth, face, hands, lips, tongue, throat or mouth

An allergic reaction can be life-threatening, particularly if anaphylaxis occurs. If patients exhibit the above symptoms, or any other symptoms associated with an allergy, they will need emergency medical treatment. Patients, their parents, guardians or caregivers, should call 911 or access help from their nearest Emergency Room if the patient develops an allergic reaction whilst being treated with Mecasermin.


When storing Mecasermin at home, patients or their caregivers should follow the manufacturer's instructions and the medication guidelines. Often, Mecasermin is supplied vials and needs to be stored in a refrigerator. However, it's important that children and/or pets cannot gain access to medication, such as Mecasermin. Parents or caregivers may want to keep a lockable medicine box in the refrigerator to ensure that the medicine is kept in a safe location at all times.

When patients are prescribed Mecasermin, they will also be given a supply of syringes, needles and other necessary equipment. These items should also be stored safely and children and/or pets should be prevented from accessing them.

A new syringe and needle should be used for each dose of Mecasermin. Once used, syringes and needles should be disposed of carefully. Patients will usually be issued with a hard, plastic box, designed for medical waste. This can be used to dispose of used syringes and needles and should be returned to a pharmacy or physician's office once it is full.

If patients are advised to discontinue treatment or if their Mecasermin vials have been opened for longer than 30 days or have reached their expiry date, the medication will need to be disposed of. However, medicines, syringes, needles and other medical equipment should never be disposed of alongside regular household waste as it could pose a risk to other people.

Instead, the patient's parents or caregivers should contact the patient's physician's office or pharmacist and use a designated medicine disposal service.


Although an insulin-like growth factor I deficiency is a fairly rare condition, it can have serious consequences if left untreated. Without effective treatment, an IGF-I deficiency will impact upon the patient's growth and prevent their cells from developing normally.

Whilst Mecasermin is not a cure for a primary IGF-I deficiency, it is an effective treatment and can be used on a long-term basis. By replacing or supplementing the patient's natural levels of IGF-I, the deficiency can be negated. Once the patient has suitable levels of IGF-I in their system, their body, organs, muscles, cartilage and bones should continue to develop at a standard rate.