macimorelin acetate at a glance
Medicine class
Growth hormone secretagogue receptor agonist and pituitary-function diagnostic agent.
Licensed use
Diagnosis of growth hormone deficiency in adults.
Administration
A healthcare professional prepares the oral suspension and supervises the test and blood sampling.
Before the test
Fasting and avoiding strenuous exercise are important because they can affect the result.
What is macimorelin acetate used for?
Macimorelin acetate is licensed for diagnostic use only.
Helping diagnose growth hormone deficiency in adults by measuring the growth hormone response after oral stimulation.
Results are interpreted alongside your history, examination and other investigations.
How does macimorelin acetate work?
Macimorelin mimics ghrelin at growth hormone secretagogue receptors in the pituitary and hypothalamus. This prompts release of stored growth hormone, which is measured in blood samples.
macimorelin acetate preparations and strengths
Oral suspension
Route: Oral
Strengths: 60 mg
How to take macimorelin acetate
Macimorelin is given as a freshly prepared oral suspension during a supervised diagnostic appointment.
Follow the clinic’s fasting instructions and avoid strenuous exercise before testing.
Tell the team about all prescribed, non-prescription and herbal products you use.
A healthcare professional prepares the suspension with water. Drink it as directed and remain fasting until sampling is complete.
Do not drive or operate machinery if you feel dizzy afterwards.
macimorelin acetate side effects
Common or expected effects
- Bitter or metallic taste
- Headache
- Fatigue
- Nausea
- Dizziness
- Diarrhoea
- Feeling hot
Get urgent medical advice
- Heart-rhythm changes, which may cause marked palpitations, severe dizziness, fainting or collapse
macimorelin acetate in pregnancy
Macimorelin is not recommended during pregnancy because human pregnancy data are unavailable and the potential risk is unknown. Tell the specialist if you are pregnant, could be pregnant or are planning pregnancy; appropriate contraception is required when it is administered.
macimorelin acetate while breastfeeding
It is unknown whether macimorelin passes into breast milk, and risk to a breastfed child cannot be excluded. The specialist should discuss whether to defer the test or interrupt breastfeeding, considering the benefits of both breastfeeding and testing.
macimorelin acetate interactions
Some medicines can alter the growth hormone response, change macimorelin exposure or increase cardiac risk. Do not stop medicines yourself; give the testing team a complete list in advance.
Strong CYP3A4 inducers, including carbamazepine, phenytoin, rifampicin and St John’s wort
They can reduce macimorelin exposure and may produce a misleading result suggesting growth hormone deficiency.
Strong CYP3A4 or P-glycoprotein inhibitors
They may increase macimorelin exposure, with uncertain effects on QT-related cardiac risk.
Growth hormone and medicines affecting its release, including somatostatin analogues, clonidine, levodopa, insulin, glucocorticoids and atropine
They can increase or suppress the growth hormone response and make the result unreliable.
Common questions about macimorelin acetate
Answers are fully visible for fast scanning and source review.
What is macimorelin acetate used for?
It is an oral stimulation test used to help diagnose growth hormone deficiency in adults.
Does macimorelin acetate treat growth hormone deficiency?
No. It is a diagnostic agent; confirmed deficiency is managed separately by the specialist team.
Why must I fast before the test?
Food reduces macimorelin exposure and may alter the growth hormone response, making the result less reliable.
Can children have this test?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.