Mecasermin
Growth hormone
Growth hormone
Recombinant human IGF-1, injected under the skin. It treats short children whose bodies cannot make IGF-1 even with normal growth hormone.
Also called: Recombinant human IGF-1 (rhIGF-1)
Quick facts
- Group
- Growth hormone
- Target
- Insulin-like growth factor 1 receptor (IGF1R)
- Used for
- Growth failure
- Key effects
- Hypoglycaemia · Snoring and enlarged tonsils
- Monitor
- Blood glucose · Growth velocity and height
- ATC
- H01AC03
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows human IGF-1 bound to the human IGF-1 receptor (cryo-EM). Mecasermin is recombinant human IGF-1.
Mecasermin is recombinant human insulin-like growth factor 1 (IGF-1), the hormone made mainly by the liver in response to growth hormone. It binds the IGF-1 receptor, a tyrosine kinase, at growth plates and other tissues and drives linear growth. It replaces IGF-1 when the problem is resistance to growth hormone, so giving growth hormone would not help. At high levels it also activates insulin receptors and lowers glucose.
- Mecasermin replaces missing IGF-1
- It activates the IGF-1 receptor tyrosine kinase
- Growth plate chondrocytes proliferate and bones lengthen
- Insulin-like action can lower blood glucose
Indications
- Growth failure in children aged 2 years and older with severe primary IGF-1 deficiency (growth hormone resistance) who do not respond to growth hormone
Adverse effects
Common
- Hypoglycaemia
- Injection-site reactions and fatty lumps (lipohypertrophy)
- Snoring and enlarged tonsils and adenoids
- Headache, ear pain and vomiting
- Joint or limb pain
Contraindications
- Active or past cancer
- Closed growth plates (epiphyses)
- Hypersensitivity to mecasermin
Key interactions
- Insulin and other glucose-lowering drugs
- Additive hypoglycaemia
- Growth hormone (somatropin)
- Not a substitute: mecasermin is used when the body cannot respond to growth hormone
What is monitored
- Blood glucose, especially when starting
- Growth velocity and height
- Tonsil size, snoring and sleep apnoea
- Fundoscopy if headache or vision changes
- Hip and knee symptoms and spine (scoliosis)
Administration and safety
- Subcutaneous injection within 20 minutes before or after a meal or carbohydrate snack
- Injection sites are rotated to avoid lipohypertrophy
Pregnancy and breastfeeding
It is a paediatric treatment; information in pregnancy is limited.
Nursing care
- Teach caregivers the signs and treatment of hypoglycaemia
- Make sure a meal or snack goes with every injection
- Ask about snoring, ear pain or sleep problems
- Report headache with vomiting or vision changes, and any limp
Pharmacokinetics
- Absorption
- Given by subcutaneous injection, usually twice a day
Test yourself
Think of the answer, then tap the question to see it.
Why does a child with primary IGF-1 deficiency need mecasermin rather than growth hormone?
The defect is resistance to growth hormone, so GH cannot raise IGF-1; mecasermin replaces IGF-1 directly.
What is the most important adverse effect of mecasermin, and how is it prevented?
Hypoglycaemia; each injection is given within 20 minutes of a meal or carbohydrate snack.
Name two contraindications to mecasermin?
Active or past cancer, and closed growth plates.
Connections
← Back to the class: Growth hormone
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Mecasermin Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.