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macrilen

Macrilen (Macimorelin Acetate) is a medication supplied as a granule, for solution.

Macimorelin Acetate · by Aeterna Zentaris

Not yet rated· sourced from the FDA label
Rated against independent regulatory sources·Last updated June 7, 2026·How we rate
Verified againstopenFDANIH DailyMedRxClass

Key facts

Active ingredient
Macimorelin Acetate
Form
Powder
Strength
Macimorelin Acetate EQ 60MG BASE/POUCH
Type
Prescription (Rx)
Brand or generic
Brand-name
Manufacturer
Aeterna Zentaris
FDA application
NDA205598
Availability
Discontinued (per FDA)

What is Macrilen?

From the FDA label:MACRILEN for oral solution is macimorelin acetate, a synthetic growth hormone secretagogue receptor agonist. Macimorelin acetate is described chemically as D-Tryptophanamide, 2-methylalanyl-N-[(1R)-1-(formylamino)-2-(1H-indol-3-yl)ethyl]-acetate. The molecular formula for macimorelin acetate is C 28 H 34 N 6 O 5 with a molecular weight of 534.6 g/mol. Figure 1: Chemical structure of macimorelin acetate Each aluminum pouch of MACRILEN contains 60 mg of macimorelin, equivalent to 68 mg of macimorelin acetate, and the following inactive ingredients: lactose monohydrate, crospovidone, sodium stearyl fumarate, saccharin sodium and colloidal silicon dioxide. figure-1

How to use

Recommended dose is 0.5 mg/kg as a single oral dose, after fasting for at least 8 hours ( 2.1 ). • See Full Prescribing Information for important preparation and administration instructions ( 2.3 ). • Discontinue therapy with strong CYP3A4 inducers, growth hormones and drugs that affect GH release for an adequate length of time before administering MACRILEN ( 2.2 ). • Adequately replace other hormone deficiencies before administering MACRILEN ( 2.2 ). 2.1 Recommended Dose The recommended dose is a single oral dose of 0.5 mg/kg of macimorelin. The dose is administered as a reconstituted solution [see Dosage and Administration ( 2.3 )] in patients fasted for at least 8 hours. 2.2 Important Recommendations Before MACRILEN Use • Discontinue strong CYP3A4 inducers prior to MACRILEN use [see Warning and Precautions ( 5.2 ) and Drug Interactions ( 7.2 )]. • Discontinue growth hormone (GH) therapy at least one week before administering MACRILEN [see Drug Interactions ( 7.3 )] . • Avoid the use of MACRILEN with drugs known to affect pituitary GH secretion [see Drug Interactions ( 7.3 )] . • For patients with deficiencies in sex hormones, thyroid hormone and/or glucocorticoid, adequately replace each of the missing hormones before administering MACRILEN. • Ensure that the patient has fasted for at least 8 hours before MACRILEN use. 2.3 Directions for Preparation and Administration…

Side effects

The most common adverse reactions were dysgeusia, dizziness, headache, fatigue, nausea, hunger, diarrhea, upper respiratory tract infection, feeling hot, hyperhidrosis, nasopharyngitis, and sinus bradycardia ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Novo Nordisk Inc. at 1-800-727-6500, or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Studies Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trial of another drug and may not reflect the rates observed in practice. The data in Table 1 are derived from an open-label, randomized, cross-over study that compared the diagnostic performance of MACRILEN to the insulin tolerance test (ITT) for the diagnosis of adult growth hormone deficiency [see Clinical Studies ( 14 )]. A total of 154 subjects with a high to low pre-test probability of having adult growth hormone deficiency received a single oral dose of 0.5 mg/kg MACRILEN. Out of 154 subjects, 58% were male, 42% female, and 86% of white origin. Median values were for age 41 years (range: 18 – 66 years) and body mass index was 27.5 kg/m 2 (range: 16 – 40 kg/m 2 ). Common adverse reactions presented in Table 1 were adverse reactions that were not present at baseline and occurred during MACRILEN dosing in at…

Warnings

Important safety information

QT Prolongation: QT prolongation can lead to development of torsade de pointes-type ventricular tachycardia. Avoid the concomitant use of MACRILEN with drugs that are known to prolong QT interval ( 5.1 , 7.1 ). • Potential for False Positive Test Results with Use of Strong CYP3A4 Inducers: Discontinue and washout strong CYP3A4 inducers before testing ( 5.2 , 7.2 ). • Potential for False Negative Test Results in Recent Onset Hypothalamic Disease: Consider repeat testing if indicated ( 5.3 ). 5.1 QT Prolongation MACRILEN causes an increase of about 11 msec in the corrected QT (QTc) interval [see Clinical Pharmacology ( 12.2 )] . QT prolongation can lead to development of torsade de pointes-type ventricular tachycardia with the risk increasing as the degree of prolongation increases. The concomitant use of MACRILEN with drugs that are known to prolong the QT interval should be avoided [see Dosage and Administration ( 2.2 ) and Drug Interactions ( 7.1 )] . 5.2 Potential for False Positive Test Results with Use of Strong CYP3A4 Inducers Concomitant use of strong CYP3A4 inducers with MACRILEN can decrease macimorelin plasma levels significantly and thereby lead to a false positive result [see Drug Interactions ( 7.2 )] . Strong CYP3A4 inducers should be discontinued and enough time should be given to allow washout of CYP3A4 inducers prior to test administration [see Dosage and Administration ( 2.2 )]. 5.3 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 may be warranted in this situation.

Who should not take Macrilen

None None ( 4 )

Overdose — what happens if you take too much

In the event of an overdose, symptomatic and supportive measures should be employed.

U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.

Interactions

7.1 Drugs that Prolong QT Interval Co-administration of MACRILEN with drugs that prolong the QT interval (such as antipsychotic medications (e.g., chlorpromazine, haloperidol, thioridazine, ziprasidone), antibiotics (e.g., moxifloxacin), Class 1A (e.g., quinidine, procainamide) and Class III (e.g., amiodarone, sotalol) antiarrhythmic medications or any other medications known to prolong the QT interval) may lead to development of torsade de pointes-type ventricular tachycardia. Avoid concomitant use of MACRILEN with drugs that prolong the QT interval. Sufficient washout time of drugs that are known to prolong the QT interval prior to administration of MACRILEN is recommended [see Dosage and Administration ( 2.2 ) and Warnings and Precautions ( 5.1 )] . 7.2 Cytochrome P450 (CYP) 3A4 Inducers Co-administration of a strong CYP3A4 inducer with MACRILEN (e.g., carbamazepine, enzalutamide, mitotane, phenytoin, rifampin, St. John's wort, bosentan, efavirenz, etravirine, modafinil, armodafinil, rufinamide) may reduce the plasma macimorelin concentrations and may lead to false positive test results. Discontinue strong CYP3A4 inducers prior to MACRILEN use. Sufficient washout time of strong CYP3A4 inducers prior to administration of MACRILEN is recommended [see Dosage and Administration ( 2.2 ) and Warnings and Precautions ( 5.2 )] . 7.3 Drugs Affecting Growth Hormone Release The following drugs may impact the accuracy of the MACRILEN diagnostic test. Avoid concomitant use of MACRILEN with the following [see Dosage and Administration ( 2.2 )] : • Drugs that directly affect the pituitary secretion of growth hormone (such as somatostatin, insulin, glucocorticoids, and cyclooxygenase inhibitors such as aspirin or indomethacin). • Drugs that may transiently elevate growth hormone concentrations (such as clonidine, levodopa, and insulin). • Drugs that may blunt the growth hormone response to MACRILEN (such as muscarinic antagonists: atropine, anti-thyroid medication: propylthiouracil, and growth hormone products). Discontinue growth hormone products at least one week before administering the MACRILEN diagnostic test. Sufficient washout time of drugs affecting growth hormone release prior to administration of MACRILEN is recommended.

Dosage forms

Powder

The forms currently marketed in the U.S., per the FDA National Drug Code Directory.

Ways to save

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Frequently asked questions

Is there a coupon or discount for Macrilen?
pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Macrilen. To pay less, ask your prescriber or pharmacist whether a generic equivalent exists, check the manufacturer's copay/savings card and patient-assistance program, and compare a pharmacy discount card against your insurance copay. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
Who makes Macrilen?
Macrilen is marketed by Aeterna Zentaris. You can see Aeterna Zentaris's full profile, rating, and other products on pharmaranks.
Is Macrilen a brand-name or generic drug?
Macrilen is a brand-name product with the active ingredient Macimorelin Acetate.
Is Macrilen available over the counter?
No. Macrilen is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
What forms does Macrilen come in?
Macrilen is currently marketed as powder, per the FDA's National Drug Code Directory.
Is Macrilen FDA-registered?
Macrilen is on record with the U.S. FDA under application number NDA205598. You can verify this on its official FDA label.
Is Macrilen safe?
There's no single safe-or-not verdict, and we don't yet have a composite recall-safety score for Macrilen. Review its FDA-label side effects and warnings below, and always consult a licensed professional.
What are the side effects of Macrilen?
Macrilen's side effects are taken directly from its FDA label. From the label: The most common adverse reactions were dysgeusia, dizziness, headache, fatigue, nausea, hunger, diarrhea, upper respiratory tract infection, feeling hot, hyperhidrosis, nasopharyngitis, and sinus bradycardia ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Novo Nordisk Inc.… Both common and serious reactions are documented in full on this page. This is general reference from the FDA, not medical advice — always consult a professional.

Clinical content sourced from the FDA label via openFDA (U.S. FDA). View the FDA label on DailyMed → Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.

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