Dosing & Uses
Dosage Forms & Strengths
granules for oral solution
- 60mg/packet (0.5mg/mL following reconstitution)
Growth Hormone Deficiency
Indicated for diagnosis of adult growth hormone (GH) deficiency
0.5 mg/kg PO as a single dose after fasting for at least 8 hr
Also see Administration
Recommendations before macimorelin use
- Sufficient washout time of drugs that are known to prolong the QT interval prior to administration of macimorelin is recommended
- Avoid concomitant use of with drugs that prolong the QT interval (eg, antipsychotic medications [eg, chlorpromazine, haloperidol, thioridazine, ziprasidone]), antibiotics [eg, moxifloxacin], class 1A antiarrhythmic medications [eg, quinidine, procainamide] and class III antiarrhythmic medications [eg, amiodarone, sotalol], any other medications known to prolong the QT interval)
- Discontinue strong CYP3A4 inducers (eg, carbamazepine, enzalutamide, mitotane, phenytoin, rifampin, St. John’s wort, bosentan, efavirenz, etravirine, modafinil, armodafinil, rufinamide)
- Discontinue GH therapy at least 1 week before macimorelin administration
- Avoid concomitant use with drugs known to affect pituitary GH secretion
- For patients with deficiencies in sex hormones, thyroid hormone, and/or glucocorticoid, adequately replace each of the missing hormones
- Ensure patient has fasted for at least 8 hr
Dosing Considerations
Clinical studies have established that a maximally stimulated serum GH level <2.8 ng/mL (ie, at the 30-, 45-, 60- and 90-minute time points) following macimorelin administration confirms the presence of adult GH deficiency
Limitation of use
- Safety and diagnostic performance have not been established with BMI >40 kg/m²
Safety and efficacy not established
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
1-10%
Dysgeusia (4.5%)
Dizziness (3.9%)
Headache (3.9%)
Fatigue (3.9%)
Nausea (3.2%)
Hunger (3.2%)
Diarrhea (1.9%)
Upper respiratory tract infection (1.9%)
Feeling hot (1.3%)
Hyperhidrosis (1.3%)
Nasopharyngitis (1.3%)
Sinus bradycardia (1.3%)
Warnings
Contraindications
None
Cautions
QT prolongation may occur; macimorelin caused an increase of ~11 msec in the corrected QT (QTc) interval; avoid concomitant use of macimorelin with drugs that are known to cause QT prolongation
Potential for false negative test results in recent onset hypothalamic disease
- Adult growth hormone (GH) deficiency caused by a hypothalamic lesion may not be detected early in the disease process
- Macimorelin acts downstream from the hypothalamus and macimorelin-stimulated release of stored GH reserves from the anterior pituitary could produce a false-negative result early when the lesion involves the hypothalamus
- Repeat testing should be considered
Drug interactions overview
- Coadministration with drugs that prolong the QT interval may lead to development of torsade de pointes-type ventricular tachycardia
- Drugs affecting growth hormone release
- Coadministration with drugs affecting GH release may impact the accuracy of the macimorelin diagnostic test; these drug include the following:
- Drugs that directly affect the pituitary secretion of GH (eg, somatostatin, insulin, glucocorticoids, and cyclooxygenase inhibitors [eg, aspirin, indomethacin])
- Drugs that may transiently elevate GH concentrations (eg, clonidine, levodopa, insulin)
- Drugs that may blunt the GH response to macimorelin (eg, muscarinic antagonists [atropine], antithyroid medication [propylthiouracil], GH products)
- Discontinue GH products at least 1 week before administering the diagnostic test
- Strong CYP3A4 inducers
- Concomitant use of strong CYP3A4 inducers can decrease macimorelin plasma levels significantly and potentially lead to a false-positive result
- Discontinue strong CYP3A4 inducers; allow enough time for a washout of CYP3A4 inducers prior to test
Pregnancy
Pregnancy
No data are available regarding use in pregnant women to inform a drug-associated risk for adverse developmental outcomes
Animal reproduction studies have not been conducted
Macimorelin is indicated as a single dose, which limits the risk of adverse developmental outcomes from macimorelin exposure
Lactation
Data are not available on the presence of macimorelin in human or animal milk, the effects on the breastfed infant, or the effects on milk production
The developmental and health benefits of breastfeeding should be considered along with the clinical need for macimorelin and any potential adverse effects on the breastfed infant from macimorelin or the underlying maternal condition
Pregnancy Categories
A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA:Information not available.
Pharmacology
Mechanism of Action
Ghrelin agonist; ghrelin is a neuropeptide released mainly from cells in the stomach and pancreas in response to hunger; ghrelin is a growth hormone-releasing peptide
It stimulates GH release by activating GH secretagogue receptors present in the pituitary and hypothalamus
Absorption
Peak plasma time, 0.5 mg/kg/dose: 0.5-1.5 hr (after fasting 8 hr)
Liquid meal decreased the macimorelin peak plasma concentration and AUC by 55% and 49%, respectively
Metabolism
An in vitro human liver microsomes study showed that CYP3A4 is the major enzyme to metabolize macimorelin
Excretion
Half-life, 0.5 mg/kg/dose: 4.1 hr
Administration
Oral Preparation
Determine the number of pouches needed to prepare dose
- For a patient weighing <120 kg: Use 1 pouch
- For a patient weighing >120 kg: Use 2 pouches
- Dissolve the entire contents of pouch(es) with the appropriate volume of water in a glass or transparent plastic container with graduation in milliliters (ie, mL)
Recommended volume per pouch
- For 1 pouch: Dissolve in 120 mL of water (corresponds to 60 mg/120 mL)
- For 2 pouches: Dissolve in 240 mL of water (corresponds to 120 mg/240 mL)
Stir solution gently for about 2-3 minutes (a small amount of undissolved particles will remain)
Final concentration of the solution is 0.5 mg/mL
Use within 30 minutes after preparation
Calculate dose and use a syringe (without a needle) with graduations in mL to measure the exact volume of macimorelin solution to be administered and transfer into a drinking glass
Discard any unused solution
Oral Administration
For oral use only
Administer diluted solution and perform the test Instruct patient to drink the entire dose within 30 seconds
Observe patient for the duration of the test
Draw venous blood samples for GH determination at 30 minutes, 45 minutes, 60 minutes, and 90 minutes after macimorelin administration
Prepare serum samples and send to a laboratory for GH determinations
Storage
Unopened pouches: Refrigerate at 2-8°C (36-46°F)
Solution must be used within 30 minutes after preparation
Discard unused portion
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Patient Handout
Formulary
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