Deflazacort is a corticosteroid used to treat Duchenne muscular dystrophy.

Brand Names
Generic Name
DrugBank Accession Number

Deflazacort, also known as Emflaza, is a corticosteroid prodrug used as an agent to manage Duchenne Muscular Dystrophy (DMD). It is marketed by Marathon Pharmaceuticals and was approved in February 2017 by the FDA.14,Label

Duchenne Muscular Dystrophy is an inherited disorder resulting from mutations of the dystrophin gene, which is important for muscle function. This disease can cause serious muscle weakness and progressive breathing and cardiovascular disability, severely impacting patient quality of life and survival.3,4,15 This disease usually manifests by muscle weakness in early childhood followed by loss of the ability to walk (ambulation) as early as age 7.4

Deflazacort delays the onset of muscle related complications resulting from DMD6, prolonging the lives of children diagnosed with this disease and exerting less harmful effects on the bone health and weight than other steroid medications.5,7

Small Molecule
Approved, Investigational
Average: 441.524
Monoisotopic: 441.215137722
Chemical Formula
  • Deflazacort
External IDs
  • MDL 458
  • MDL-458



Deflazacort is indicated for the treatment of Duchenne Muscular Dystrophy (DMD) in patients 2 years of age and older.Label

Reduce drug development failure rates
Build, train, & validate machine-learning models
with evidence-based and structured datasets.
See how
Build, train, & validate predictive machine-learning models with structured datasets.
See how
Associated Conditions
Indication TypeIndicationCombined Product DetailsApproval LevelAge GroupPatient CharacteristicsDose Form
Management ofDuchenne muscular dystrophy••••••••••••
Contraindications & Blackbox Warnings
Prevent Adverse Drug Events Today
Tap into our Clinical API for life-saving information on contraindications & blackbox warnings, population restrictions, harmful risks, & more.
Learn more
Avoid life-threatening adverse drug events with our Clinical API
Learn more

Deflazacort exerts anti-inflammatory activity in DMD, likely improving various symptoms, including muscle weakness and cardiorespiratory symptoms in addition to delaying their onset.6 This allows for an increased quality of life and prevents the necessity for surgical procedures, such as those for scoliosis, which is associated with DMD. Studies showed significant preservation of muscle mass in patients generally treated with 0.9 mg/kg/day of deflazacort compared to a control group. The following findings are based on clinical studies using deflazacort on a long term basis6,8:

Effects on muscle strength

At age 16, individuals treated with long-term deflazacort had 63 ± 4% score in muscle strength compared to a mean muscle strength score of 31 ± 3% for control patients6. Significant improvements in climbing stairs and rising from a supine position were also seen in patients taking deflazacort.6

Effects on ambulation

Ambulation was significantly higher by 12 years of age and 18 years of age in patients taking deflazacort when compared with the control group. The control group showed a mean loss of ambulation of 2 years sooner than with deflazacort treatment.8

Effects on cardiac function

Mean left ventricular ejection fraction (a measure of cardiac function) was higher in patients treated with deflazacort over the long term. Preservation of cardiac function was demonstrated by a mean difference in ejection fraction of about 7%, favoring study groups taking deflazacort over control groups.8

Effects on spinal alignment

Children treated with deflazacort also significantly lowered the rate and severity of scoliosis and eliminated the need for scoliosis surgery after long-term treatment.6,8

Mechanism of action

Deflazacort is a corticosteroid prodrug with an active metabolite, 21-deflazacort, which binds to the glucocorticoid receptor to exert anti-inflammatory and immunosuppressive effects on the body.1,9,10 The exact mechanism by which deflazacort exerts its therapeutic effects in patients with DMD is unknown but likely occurs via its anti-inflammatory activities.Label

UGlucocorticoid receptor

Deflazacort is rapidly absorbed after oral administration with peak concentration occurring within 1-2 hours.10,Label One pharmacokinetic study determined an AUC (area under the curve) of 280 ng/ml · h.1

The bioavailability of both the oral suspension and tablet are similar.Label In clinical studies, coadministration of deflazacort crushed with food or applesauce did not affect absorption or bioavailability.Label

Volume of distribution

One study determined the volume of distribution to be 204 ± 84 L.1

Protein binding

The protein binding of the active metabolite of deflazacort is approximately 40%.Label,12


After oral ingestion, deflazacort is deacetylated at position 21 by plasma esterases, producing the active metabolite 21-deflazacort.1,10,Label,16 21-deflazacort is then further metabolized by CYP3A4 to inactive metabolite products.Label,13 Deflazacort 21-OH metabolism is extensive. The metabolite of deflazacort-21-OH is deflazacort 6-beta-OH.13,16

Hover over products below to view reaction partners

Route of elimination

Urinary excretion is the major route of deflazacort elimination, accounting for about about 70% of the excreted dose.1 The remainder of the dose (about 30%) is excreted in the feces1. Elimination is almost completed by 24 hours post-dose.11 21-deflazacort makes up about 18% of the eliminated drug in the urine.Label


The half-life of deflazacort ranges from 1.1 to 1.9 h 1,16


114 ±27 L/h, according to one noncompartmental pharmacokinetic study.1

The clearance of corticosteroids is enhanced in hypothyroid patients and increased in patients with hyperthyroidism. Dosing adjustments may be considered according to thyroid status.Label A study of corticosteroid clearance was performed in patients with a creatinine clearance of 15 mL/min or less, and determined that the active metabolite of deflazacort, 21-deflazacort was similar to that in patients with normal renal clearance.Label

Adverse Effects
Improve decision support & research outcomes
With structured adverse effects data, including: blackbox warnings, adverse reactions, warning & precautions, & incidence rates. View sample adverse effects data in our new Data Library!
See the data
Improve decision support & research outcomes with our structured adverse effects data.
See a data sample

The LD50 for the oral dose is 5200 mg/kg (mouse); Oral TDLO (woman): 0.12 mg/kgMSDS

A note on altered endocrine function and immunosuppression

Deflazacort, as a steroid prodrug used over a long-term period, can cause hormone imbalance leading to diseases such as Cushing's Syndrome and hypothalamic-pituitary-adrenal axis suppression. It can also predispose to infection, as it promotes immunosuppression.10 It is important to monitor for hormonal imbalance and infection and provide necessary treatment if they occur.Label


Mutagenicity assays were negative in various laboratory and in vivo assays performed on rats.Label,16 Chronic use in mice for 2 years in one study resulted in a higher rate of osteoma and osteosarcomas in mice receiving 0.06, 0.12, 0.25, 0.50, or 1.0 mg/kg of deflazacort daily.Label

Use in pregnancy

There are no sufficient data to support the administration of deflazacort during pregnancy. Corticosteroid drugs such as deflazacort should only be used during pregnancy only if the benefits of therapy outweigh the potential risks.Label,16

Use in lactation

Corticosteroids, when administered systemically, are excreted in the breastmilk. Exposure may lead to disturbances in bone development and growth and endocrine disturbances in the exposed infant.Label,16

Not Available
Pharmacogenomic Effects/ADRs
Not Available


Drug Interactions
This information should not be interpreted without the help of a healthcare provider. If you believe you are experiencing an interaction, contact a healthcare provider immediately. The absence of an interaction does not necessarily mean no interactions exist.
AbametapirThe serum concentration of Deflazacort can be increased when it is combined with Abametapir.
AbataceptThe risk or severity of adverse effects can be increased when Abatacept is combined with Deflazacort.
AbemaciclibThe metabolism of Abemaciclib can be increased when combined with Deflazacort.
AcalabrutinibThe metabolism of Acalabrutinib can be increased when combined with Deflazacort.
AcarboseThe risk or severity of hyperglycemia can be increased when Deflazacort is combined with Acarbose.
Food Interactions
  • Avoid grapefruit products. Grapefruit inhibits CYP3A metabolism, which may increase the serum concentration of deflazacort.
  • Avoid St. John's Wort. This herb induces CYP3A metabolism and may reduce serum levels of deflazacort.
  • Take with or without food. The tablets may be crushed and mixed with applesauce and consumed immediately.


Drug product information from 10+ global regions
Our datasets provide approved product information including:
dosage, form, labeller, route of administration, and marketing period.
Access now
Access drug product information from over 10 global regions.
Access now
International/Other Brands
Calcort (Shire) / Cortax / Decortil / Deflanil / MOAID / Xalcort (Beacon Pharmaceuticals Limited) / Zamen
Brand Name Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing EndRegionImage
EmflazaTablet18 mg/1OralMarathon Pharmaceuticals, LLC2017-02-092020-06-30US flag
EmflazaTablet36 mg/1OralMarathon Pharmaceuticals, LLC2017-02-092020-06-30US flag
EmflazaTablet36 mg/1OralPtc Therapeutics, Inc.2018-09-10Not applicableUS flag
EmflazaTablet6 mg/1OralPtc Therapeutics, Inc.2018-09-10Not applicableUS flag
EmflazaTablet6 mg/1OralMarathon Pharmaceuticals, LLC2017-02-092020-06-30US flag
Generic Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing EndRegionImage
DeflazacortTablet18 mg/1OralAurobindo Pharma Limited2024-02-09Not applicableUS flag
DeflazacortTablet36 mg/1OralAurobindo Pharma Limited2024-02-09Not applicableUS flag
DeflazacortTablet6 mg/1OralAurobindo Pharma Limited2024-02-09Not applicableUS flag
DeflazacortTablet30 mg/1OralAurobindo Pharma Limited2024-02-09Not applicableUS flag
Deflazacort Oral SuspensionSuspension22.75 mg/1mLOralTris Pharma Inc2024-05-01Not applicableUS flag


ATC Codes
H02AB13 — Deflazacort
Drug Categories
Chemical TaxonomyProvided by Classyfire
This compound belongs to the class of organic compounds known as gluco/mineralocorticoids, progestogins and derivatives. These are steroids with a structure based on a hydroxylated prostane moiety.
Organic compounds
Super Class
Lipids and lipid-like molecules
Steroids and steroid derivatives
Sub Class
Pregnane steroids
Direct Parent
Gluco/mineralocorticoids, progestogins and derivatives
Alternative Parents
20-oxosteroids / 11-beta-hydroxysteroids / 3-oxo delta-1,4-steroids / Delta-1,4-steroids / Alpha-acyloxy ketones / Oxazolines / Secondary alcohols / Imidoesters / Cyclic ketones / Cyclic alcohols and derivatives
show 9 more
11-beta-hydroxysteroid / 11-hydroxysteroid / 20-oxosteroid / 3-oxo-delta-1,4-steroid / 3-oxosteroid / Alcohol / Aliphatic heteropolycyclic compound / Alpha-acyloxy ketone / Azacycle / Carbonyl group
show 24 more
Molecular Framework
Aliphatic heteropolycyclic compounds
External Descriptors
Not Available
Affected organisms
  • Humans and other mammals

Chemical Identifiers

CAS number
InChI Key
2-[(1S,2S,4R,8S,9S,11S,12S,13R)-11-hydroxy-6,9,13-trimethyl-16-oxo-5-oxa-7-azapentacyclo[²,⁹.0⁴,⁸.0¹³,¹⁸]icosa-6,14,17-trien-8-yl]-2-oxoethyl acetate


General References
  1. Mollmann H, Hochhaus G, Rohatagi S, Barth J, Derendorf H: Pharmacokinetic/pharmacodynamic evaluation of deflazacort in comparison to methylprednisolone and prednisolone. Pharm Res. 1995 Jul;12(7):1096-100. [Article]
  2. Ding W, Ding L, Li WB, Pan H, Lin HD: [Pharmacokinetics of deflazacort tablets in healthy Chinese volunteers]. Yao Xue Xue Bao. 2014 Jun;49(6):921-6. [Article]
  3. Falzarano MS, Scotton C, Passarelli C, Ferlini A: Duchenne Muscular Dystrophy: From Diagnosis to Therapy. Molecules. 2015 Oct 7;20(10):18168-84. doi: 10.3390/molecules201018168. [Article]
  4. Gao QQ, McNally EM: The Dystrophin Complex: Structure, Function, and Implications for Therapy. Compr Physiol. 2015 Jul 1;5(3):1223-39. doi: 10.1002/cphy.c140048. [Article]
  5. Joshi N, Rajeshwari K: Deflazacort. J Postgrad Med. 2009 Oct-Dec;55(4):296-300. doi: 10.4103/0022-3859.58942. [Article]
  6. McAdam LC, Mayo AL, Alman BA, Biggar WD: The Canadian experience with long-term deflazacort treatment in Duchenne muscular dystrophy. Acta Myol. 2012 May;31(1):16-20. [Article]
  7. Ferraris JR, Pasqualini T, Legal S, Sorroche P, Galich AM, Pennisi P, Domene H, Jasper H: Effect of deflazacort versus methylprednisone on growth, body composition, lipid profile, and bone mass after renal transplantation. The Deflazacort Study Group. Pediatr Nephrol. 2000 Jul;14(7):682-8. [Article]
  8. Houde S, Filiatrault M, Fournier A, Dube J, D'Arcy S, Berube D, Brousseau Y, Lapierre G, Vanasse M: Deflazacort use in Duchenne muscular dystrophy: an 8-year follow-up. Pediatr Neurol. 2008 Mar;38(3):200-6. doi: 10.1016/j.pediatrneurol.2007.11.001. [Article]
  9. Campbell C, Jacob P: Deflazacort for the treatment of Duchenne Dystrophy: a systematic review. BMC Neurol. 2003 Sep 8;3:7. doi: 10.1186/1471-2377-3-7. Epub 2003 Sep 8. [Article]
  10. Parente L: Deflazacort: therapeutic index, relative potency and equivalent doses versus other corticosteroids. BMC Pharmacol Toxicol. 2017 Jan 5;18(1):1. doi: 10.1186/s40360-016-0111-8. [Article]
  11. Assandri A, Buniva G, Martinelli E, Perazzi A, Zerilli L: Pharmacokinetics and metabolism of deflazacort in the rat, dog, monkey and man. Adv Exp Med Biol. 1984;171:9-23. [Article]
  12. Nayak S, Acharjya B: Deflazacort versus other glucocorticoids: a comparison. Indian J Dermatol. 2008;53(4):167-70. doi: 10.4103/0019-5154.44786. [Article]
  13. Deshmukh R, Sharma L, Tekade M, Kesharwani P, Trivedi P, Tekade RK: Force degradation behavior of glucocorticoid deflazacort by UPLC: isolation, identification and characterization of degradant by FTIR, NMR and mass analysis. J Biomed Res. 2016 Mar;30(2):149-161. doi: 10.7555/JBR.30.20150074. Epub 2016 Feb 20. [Article]
  14. FDA approval information [Link]
  15. Duchenne Muscular Dystrophy organization page [Link]
  16. Calcort 6mg tablets, Medicines UK [Link]
  17. FDA Approved Drug Products: Emflaza (deflazacort) tablets [Link]
PubChem Compound
PubChem Substance
Download (24.1 KB)

Clinical Trials

Clinical Trials
Clinical Trial & Rare Diseases Add-on Data Package
Explore 4,000+ rare diseases, orphan drugs & condition pairs, clinical trial why stopped data, & more. Preview package
PhaseStatusPurposeConditionsCountStart DateWhy Stopped100+ additional columns
4Active Not RecruitingPreventionImpacted Third Molar Tooth1somestatusstop reasonjust information to hide
4CompletedTreatmentRenal Disease, Chronic1somestatusstop reasonjust information to hide
3CompletedTreatmentDuchenne Muscular Dystrophy (DMD)1somestatusstop reasonjust information to hide
3TerminatedTreatmentLimb Girdle Muscular Dystrophy1somestatusstop reasonjust information to hide
3WithdrawnTreatmentDuchenne Muscular Dystrophy (DMD)1somestatusstop reasonjust information to hide


Not Available
Not Available
Dosage Forms
SuspensionOral22.75 mg
TabletOral6.00 mg
TabletOral6.000 mg
TabletOral30 mg
SuspensionOral2275000 mg
TabletOral3000000 mg
TabletOral6 mg
SuspensionOral22.75 mg/1mL
TabletOral18 mg/1
TabletOral30 mg/1
TabletOral36 mg/1
TabletOral6 mg/1
Solution / dropsOral
TabletOral600000 mg
TabletOral30.000 mg
TabletOral30.00 mg
Not Available
Not Available


Experimental Properties
melting point (°C)>215 C
water solubility108 μg/mL
Predicted Properties
Water Solubility0.0175 mg/mLALOGPS
pKa (Strongest Acidic)14.74Chemaxon
pKa (Strongest Basic)0.48Chemaxon
Physiological Charge0Chemaxon
Hydrogen Acceptor Count5Chemaxon
Hydrogen Donor Count1Chemaxon
Polar Surface Area102.26 Å2Chemaxon
Rotatable Bond Count4Chemaxon
Refractivity117.12 m3·mol-1Chemaxon
Polarizability46.79 Å3Chemaxon
Number of Rings5Chemaxon
Rule of FiveYesChemaxon
Ghose FilterYesChemaxon
Veber's RuleNoChemaxon
MDDR-like RuleNoChemaxon
Predicted ADMET Features
Not Available


Mass Spec (NIST)
Not Available
SpectrumSpectrum TypeSplash Key
Predicted MS/MS Spectrum - 10V, Positive (Annotated)Predicted LC-MS/MSsplash10-007o-0009300000-f6dfaeb1ba93bd86229e
Predicted MS/MS Spectrum - 10V, Negative (Annotated)Predicted LC-MS/MSsplash10-0007-0006900000-09c635d16cf1f755a47e
Predicted MS/MS Spectrum - 20V, Negative (Annotated)Predicted LC-MS/MSsplash10-0a4i-9002100000-c5948fa3d8e1aea7b67c
Predicted MS/MS Spectrum - 20V, Positive (Annotated)Predicted LC-MS/MSsplash10-006x-0319500000-7bcfc2ee37a444687882
Predicted MS/MS Spectrum - 40V, Negative (Annotated)Predicted LC-MS/MSsplash10-0ktf-5119000000-796843895f54ad0708bb
Predicted MS/MS Spectrum - 40V, Positive (Annotated)Predicted LC-MS/MSsplash10-006y-0944200000-fe046a0b8cec0cd97222
Predicted 1H NMR Spectrum1D NMRNot Applicable
Predicted 13C NMR Spectrum1D NMRNot Applicable
Chromatographic Properties
Collision Cross Sections (CCS)
AdductCCS Value (Å2)Source typeSource
DarkChem Lite v0.1.0
DarkChem Lite v0.1.0
DeepCCS 1.0 (2019)
DarkChem Lite v0.1.0
DarkChem Lite v0.1.0
DeepCCS 1.0 (2019)
DarkChem Lite v0.1.0
DeepCCS 1.0 (2019)


Build, predict & validate machine-learning models
Use our structured and evidence-based datasets to unlock new
insights and accelerate drug research.
Learn more
Use our structured and evidence-based datasets to unlock new insights and accelerate drug research.
Learn more
Pharmacological action
General Function
Zinc ion binding
Specific Function
Receptor for glucocorticoids (GC). Has a dual mode of action: as a transcription factor that binds to glucocorticoid response elements (GRE), both for nuclear and mitochondrial DNA, and as a modula...
Gene Name
Uniprot ID
Uniprot Name
Glucocorticoid receptor
Molecular Weight
85658.57 Da
  1. Mollmann H, Hochhaus G, Rohatagi S, Barth J, Derendorf H: Pharmacokinetic/pharmacodynamic evaluation of deflazacort in comparison to methylprednisolone and prednisolone. Pharm Res. 1995 Jul;12(7):1096-100. [Article]
  2. FDA Approved Drug Products: Emflaza (deflazacort) tablets [Link]


Pharmacological action
General Function
Vitamin d3 25-hydroxylase activity
Specific Function
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It performs a variety of oxidation react...
Gene Name
Uniprot ID
Uniprot Name
Cytochrome P450 3A4
Molecular Weight
57342.67 Da
  1. Yu J, Petrie ID, Levy RH, Ragueneau-Majlessi I: Mechanisms and Clinical Significance of Pharmacokinetic-Based Drug-Drug Interactions with Drugs Approved by the U.S. Food and Drug Administration in 2017. Drug Metab Dispos. 2019 Feb;47(2):135-144. doi: 10.1124/dmd.118.084905. Epub 2018 Nov 15. [Article]
  2. Dvorak Z, Pavek P: Regulation of drug-metabolizing cytochrome P450 enzymes by glucocorticoids. Drug Metab Rev. 2010 Nov;42(4):621-35. doi: 10.3109/03602532.2010.484462. [Article]
  3. Deflazacort FDA label [Link]
Pharmacological action
General Function
Oxygen binding
Specific Function
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
Gene Name
Uniprot ID
Uniprot Name
Cytochrome P450 3A5
Molecular Weight
57108.065 Da
  1. Dvorak Z, Pavek P: Regulation of drug-metabolizing cytochrome P450 enzymes by glucocorticoids. Drug Metab Rev. 2010 Nov;42(4):621-35. doi: 10.3109/03602532.2010.484462. [Article]

Drug created at October 20, 2016 21:00 / Updated at October 07, 2021 12:09