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Prescription medicine

Busulfan Brand names: Myleran

Busulfan (Myleran) is a prescription medicine with an FDA approval on record since 1954. FDA's NDC Directory lists it from 7 generic labelers.

  • Generic listed
  • A presentation discontinued
  • Boxed warning

Check it at the source: the busulfan FDA label on DailyMed (effective June 27, 2024, Eugia US LLC); the NDA 9386 record on Drugs@FDA; every busulfan label on DailyMed.

Highlights of the record

FDA label of June 27, 2024; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026

Boxed warning

MYELOSUPPRESSION.

Busulfan injection causes severe and prolonged myelosuppression at the recommended dosage. Hematopoietic progenitor cell transplantation is required to prevent potentially fatal complications of the prolonged myelosuppression [see Warnings and Precautions (5.1) ]. WARNING: MYELOSUPPRESSION See full prescribing information for complete boxed warning. Causes severe and prolonged myelosuppression. ( 5.1 ) Hematopoietic progenitor cell transplantation is required to prevent potentially fatal complications of the prolonged myelosuppression.

Used for

From the label: indications and usage

Busulfan injection is indicated for use in combination with cyclophosphamide as a conditioning regimen prior to allogeneic hematopoietic progenitor cell transplantation for chronic myelogenous leukemia.

Forms and strengths

  • 2 mg
  • 6 mg/ml

Injection (solution); injection; film-coated tablet; injection (solution) (concentrate).

On the market

Earliest approval on file
June 26, 1954 Myleran, Waylis Therap; Drugs@FDA’s file, where older or withdrawn approvals can be missing
Generic approvals
15 first December 22, 2015; 7 with a marketed status in Drugs@FDA
Labelers listed (NDC)
8 of which 7 under generic applications, 1 under brand applications, repackagers included

Supply and safety

Pharmacy cost (NADAC)
Not in the survey
Shortage (FDA)
None current 1 past records
Recalls by its makers (FDA)
1 since 2020 0 Class I among all firms' recalls; latest May 4, 2026; 1 more by firms not listed as its makers
FAERS reports
15,644 through July 30, 2026

What is busulfan used for?

From the label: indications and usage

Busulfan injection is indicated for use in combination with cyclophosphamide as a conditioning regimen prior to allogeneic hematopoietic progenitor cell transplantation for chronic myelogenous leukemia. Busulfan injection is an alkylating drug indicated for: Use in combination with cyclophosphamide as a conditioning regimen prior to allogeneic hematopoietic progenitor cell transplantation for chronic myelogenous leukemia (CML)

Conditions named in the indications of busulfan's FDA labels, with every medicine labeled for each:

From other busulfan labels

Leukemia, lymphoma and myeloma: INDICATIONS AND USAGE MYLERAN (busulfan) is indicated for the palliative treatment of chronic myelogenous (myeloid, myelocytic, granulocytic) leukemia.

FDA pharmacologic class: Alkylating Drug.

Source: FDA drug label (Busulfan), Eugia US LLC, effective June 27, 2024 (SPL set 06883ac0-4b2a-4f26-89bf-512d37b9ba7f), via openFDA; the full label on DailyMed

Is there a generic for busulfan (Myleran)?

The FDA approved the first generic busulfan on December 22, 2015. 15 generic applications are approved; 7 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.

FDA's NDC Directory lists busulfan from 7 labelers under a generic (ANDA) application and from 1 brand labeler. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.

  • 1954 earliest approval on file
  • 2015 first generic approved
  • red ticks recalls

Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)

Is busulfan in shortage?

No busulfan presentation is listed as in shortage in the FDA Drug Shortage Database (read October 8, 2026); its 1 record is all marked to be discontinued, the latest updated October 24, 2025. ASHP keeps a separate shortage list, which can differ.

PresentationCompanyStatusUpdated
Busulfan, Injection, 6 mg/1 mL (NDC 67457-893-08)Mylan Institutional, a Viatris CompanyTo Be DiscontinuedOctober 24, 2025

Every busulfan presentation in the FDA shortage database

Source: FDA Drug Shortage Database via openFDA, updated October 8, 2026

Has busulfan been recalled?

The FDA's Enforcement Report lists 2 recalls naming busulfan since 2020: 0 Class I (the most serious), 1 Class II, 1 Class III; 1 still ongoing. 1 of them is by a firm that FDA's NDC Directory does not list as a maker of busulfan and that holds no application for it in Drugs@FDA, such as compounding pharmacies or bulk-ingredient suppliers; the recall notice names the product recalled. A recall names products and lots, not every product of the medicine.

StartedClassCompanyReason
May 4, 2026Class IIISagent PharmaceuticalsFailed Impurities/Degradation Specifications
December 8, 2020Class IIShilpa Medicare Limited not a listed makerCGMP Deviations

Source: FDA Enforcement Report (drug recalls) via openFDA, through October 8, 2026

What does the busulfan label say about other medicines?

The busulfan label names 12 other medicines in its interaction, contraindication or warning sections. The labels of 9 other medicines name busulfan. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.

Medicine namedSectionWhat the label says
Acetaminophendrug interactionsDRUG INTERACTIONS Drugs that Decrease Busulfan Clearance: Metronidazole, itraconazole, iron chelating agents, acetaminophen. ( 7.1 ) Drugs that Increase Busulfan Clearance:
Cyclophosphamidewarnings and precautionsAdvise of potential risk to a fetus and use of effective contraception ( 5.4 , 8.1 , 8.3 ) Cardiac tamponade has been reported in pediatric patients with thalassemia who received high doses of oral busulfan and cyclophosphamide.
Deferasiroxdrug interactionsDecreased clearance of busulfan was observed with concomitant use with deferasirox.
Divalproexwarnings and precautionsInitiate phenytoin therapy or any other alternative anti-convulsant prophylactic therapy (e.g., benzodiazepines, valproic acid or levetiracetam) prior to busulfan treatment [see Dosage and Administration (2.1) ].
Filgrastimwarnings and precautionsThe absolute neutrophil count recovered at a median of 13 days following allogeneic transplantation when prophylactic filgrastim was used in the majority of patients.
Fluconazoledrug interactionsFluconazole (200 mg) has been used with busulfan.
Itraconazoledrug interactionsDRUG INTERACTIONS Drugs that Decrease Busulfan Clearance: Metronidazole, itraconazole, iron chelating agents, acetaminophen. ( 7.1 ) Drugs that Increase Busulfan Clearance:
Levetiracetamwarnings and precautionsInitiate phenytoin therapy or any other alternative anti-convulsant prophylactic therapy (e.g., benzodiazepines, valproic acid or levetiracetam) prior to busulfan treatment [see Dosage and Administration (2.1) ].
Metronidazoledrug interactionsDRUG INTERACTIONS Drugs that Decrease Busulfan Clearance: Metronidazole, itraconazole, iron chelating agents, acetaminophen. ( 7.1 ) Drugs that Increase Busulfan Clearance:
Phenytoindrug interactionsDrugs that Increase Busulfan Clearance Phenytoin increases the clearance of busulfan by 15% or more, possibly due to the induction of glutathione-S-transferase.
Thioguaninedrug interactionsLong-term continuous therapy with thioguanine and busulfan should be used with caution.
Valproic acidwarnings and precautionsInitiate phenytoin therapy or any other alternative anti-convulsant prophylactic therapy (e.g., benzodiazepines, valproic acid or levetiracetam) prior to busulfan treatment [see Dosage and Administration (2.1) ].

Other labels that name busulfan

Check busulfan against other medicines

Source: FDA drug label (Busulfan), Eugia US LLC, effective June 27, 2024 (SPL set 06883ac0-4b2a-4f26-89bf-512d37b9ba7f), via openFDA; the full label on DailyMed

What do FAERS reports show for busulfan?

The FDA Adverse Event Reporting System holds 15,644 reports that list busulfan among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 4,592 are coded as a death and 3,233 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.

Reports received each year

The most reported reactions

  • Off Label Use (a use or a product term, not a reaction)2,019
  • Product Use In Unapproved Indication (a use or a product term, not a reaction)1,723
  • Mucosal Inflammation1,113
  • Drug Ineffective (a use or a product term, not a reaction)1,076
  • Graft Versus Host Disease (named in the label)915
  • Venoocclusive Liver Disease875
  • Cytomegalovirus Infection873
  • Febrile Neutropenia (named in the label)863

Side effects: the label's list and every FAERS reaction

Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026

What next?

Other alkylating drugs
the pharmacologic class, with prices and generics
Busulfan side effects
the label's list beside FAERS reports
Busulfan shortage record
every presentation, company and date
Check an interaction
what two or more labels say about each other