Home › NDC Lookup › Ingredients › Zileuton › 51407-0741-12
Zileuton 600 mg Tablet, Multilayer, Extended Release, 120-count — NDC 51407-0741-12 package photo
Label image from the product's FDA listing (DailyMed) — may show a different pack size or an older label revision.

Zileuton 600 mg Tablet, Multilayer, Extended Release, 120-count — NDC 51407-741-12 (Billing 51407-0741-12)

by Golden State Medical Supply, Inc. · 120 TABLET, MULTILAYER, EXTENDED RELEASE in 1 BOTTLE

This is a package of 120 tablets of Zileuton 600 mg Tablet, Multilayer, Extended Release from Golden State Medical Supply, Inc., marketed since Dec 2019 and currently FDA-listed. It is this product's only package size.

NDC 51407-0741-12
🏷️ FDA NDC (as labeled) 51407-741-12 billing pads the product segment with a zero
Rx only Generic On market Non-controlled ⇄ Compare with another NDC
🗂️ FDA directory synced Oct 1, 2026 · this listing last changed Jul 24, 2026 · sources: openFDA · FDA label (DailyMed) · FDA Orange & Purple Book · First Databank · CMS NADAC, ASP, Medicare & Medicaid · RxNorm
📋 All sources & update times →

This page is curated, coded, and maintained by

Compiled from public FDA, CMS, DailyMed, NADAC, and related drug data sources. Editorial policy

Identity & classification

Regulatory identifiers FDA, NLM and CMS codes for this package

FDA NDC (as labeled) 51407-741-12
Product NDC 51407-741
11-digit billing NDC 51407074112
NCPDP billing unit EA — each (per item)
RxCUI 730834
UNII V1L22WVE2S
Application # ANDA212670
SPL Set ID f7573809-7741-04c9-e053-6294a90ab193
Established class (EPC) 5-Lipoxygenase Inhibitor
Mechanism of action 5-Lipoxygenase Inhibitors
Physiologic effect Decreased Leukotriene Production
DEA schedule Non-controlled
Marketing category ANDA
Marketing status On market
FDA listing status Listed (active directory)
Marketing start 2019-12-16
Route ORAL
Dosage form TABLET, MULTILAYER, EXTENDED RELEASE
Substance ZILEUTON
TE code (Orange Book) AB · RLD · RS

Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification

GCN Seq No 063062
GCN 98822
HICL code 012321
Ingredient (HICL) Zileuton
HIC1 code Z
Therapeutic class — broad (HIC1) Body As A Whole
HIC2 code Z4
Therapeutic class — intermediate (HIC2) Eicosanoids
HIC3 code Z4E
Therapeutic class — specific (HIC3) 5-Lipoxygenase Inhibitors
AHFS code 48:10.24.00
AHFS class Leukotriene Modifiers
FDB label name ZILEUTON ER 600 MG TABLET
FDB brand name Zileuton Er
Legend status F — Federal legend — prescription drug or device
Quick answers
  • GSN (GCN sequence number): 063062
  • GCN: 98822
  • HICL (First Databank): 012321
  • AHFS class code: 48:10.24.00
  • RxCUI (RxNorm): 730834
Why two NDCs? The FDA registers this code as 51407-741-12 — a 5-3-2 layout, and that's what's printed on the package and shown on DailyMed. For insurance claims, every NDC is standardized to a uniform 11-digit 5-4-2 format by adding a zero to the product segment → 51407-0741-12. Same drug, same package — only the format differs.
Where does this data come from?
Identifiers from the FDA openFDA NDC Directory and Structured Product Labeling; RxCUI from RxNorm (NLM); GPI from Medi-Span; GCN / HIC / AHFS / legend from First Databank.

RxNorm drug class

This medicine belongs to the 5-Lipoxygenase Inhibitor class.

Pharmacologic class 5-Lipoxygenase Inhibitor
How it works 5-Lipoxygenase Inhibitors
Where does this data come from?
Therapeutic classes from RxNorm RxClass (U.S. National Library of Medicine) — Established Pharmacologic Class (FDA), ATC drug family (WHO) and mechanism of action, matched by this product’s RxCUI.

Clinical

Label name ZILEUTON ER 600 MG TABLET Ingredient Zileuton
📗 Our plain-language guide HelloPharmacist
  • No — zileuton is a controller medicine, not a rescue medicine. It works slowly over time to reduce airway inflammation and prevent attacks, but it won't open your airways quickly d...
  • Can I use zileuton to stop an asthma attack that's already happening?
  • Zileuton can raise liver enzyme levels, and in some people this can lead to real liver injury. Regular blood tests — especially a liver enzyme called ALT — let your doctor catch an...
  • Why do I need blood tests while taking zileuton?
📖 Read our full Zileuton guide →
Where does this data come from?
Plain-language summary from MedlinePlus (U.S. National Library of Medicine); supplement & herbal interactions and nutrient depletion data from the Natural Medicines database; our full guide is HelloPharmacist editorial content.

Pricing

A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.

Price systemPer eachPer package
Retail pharmacies payNADAC · weekly Not in the retail survey — common for institutional, discontinued, or low-volume packs.
Medicaid paysCMS SDUD · 12 mo No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data.
Medicare drug plans payPart D · Q2 2026 $17.64 $2,116.57 / 120 tablets
Where does this data come from?
NADAC (National Average Drug Acquisition Cost) is the CMS weekly pharmacy-acquisition-cost survey — what pharmacies pay. ASP (Average Sales Price) is the CMS Medicare Part B drug-payment file, published quarterly. Medicaid pays is computed by us from CMS State Drug Utilization Data (total reimbursed ÷ units, trailing 12 months) — gross of rebates and inclusive of dispensing fees, so it reflects what Medicaid paid, not an acquisition cost. Medicare drug plans pay is the median negotiated point-of-sale unit cost across plans listing this NDC in the CMS quarterly Prescription Drug Plan pricing files, before rebates. The VA pays is the federal contract price (FSS, and the statutory Big 4 ceiling where listed) from the VA National Acquisition Center pharmaceutical price file. All are free public government data; each measures a different payer, so the figures are not directly comparable.

Packaging — all sizes for this product

Package NDCDescription Marketing startMarketing endStatus
51407-0741-12 You're viewing this Main listing 120 TABLET, MULTILAYER, EXTENDED RELEASE in 1 BOTTLE 2023-01-19 — Active

Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Zileuton 600 mg 31722-0044-12 Camber 120 tablets $2.049 AB Availability likely —
Zileuton 600 mg 64380-0189-01 Strides 120 tablets $2.049 AB Availability likely —
Zileuton 600 mg 64980-0206-12 Rising 120 tablets $2.049 AB Availability likely —
Zileuton 600 mg 72603-0246-01 NorthStar 120 tablets $2.049 AB Availability likely —
Zileuton 600 mgthis 51407-0741-12 Golden 120 tablets — AB FDA listed —
About this product: this is a generic version of the medicine. FDA equivalence ratings are shown when available, and other versions are listed above, least expensive first.
Where does this data come from?
Equivalents are other NDCs of the same ingredient, form and route from the openFDA NDC Directory, ranked least-expensive-first by NADAC. Therapeutic-equivalence (AB) ratings come from the FDA Orange Book; biologics use the FDA Purple Book for biosimilar & interchangeable status.

Availability & generic status

🏛️
2019
On the market since
Dec 2019
📍
2026
Currently FDA-listed
7 years listed
🔓
·
Generic on the market
this product is a generic
✅This is a generic drug

This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.

Where does this data come from?
Patents and exclusivity from the FDA Orange Book (small-molecule drugs), refreshed from public FDA data. Generic launch timing is an estimate, not a guarantee.

What it looks like

Color white
ShapeOval
ImprintP723
Size19 mm
ScoringNot scored
One label can cover several strengths, so colors may be combined — always confirm a loose pill against the dispensed prescription label or a pharmacist.
Where does this data come from?
Physical description (imprint, shape, color, scoring, coating) from this product’s FDA Structured Product Labeling (SPL), mirrored from DailyMed / openFDA.

Inactive Ingredients / Excipients

Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.

💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.

  • UNII 1K09F3G675
    Ferric oxide red is an inorganic iron compound used as a colorant in medicines. It gives tablets, capsules, or other dosage forms a red or reddish tint for identification and appearance.
  • UNII 73CJJ317SR
    A waxy substance derived from plant oils, used as a binder and lubricant to help hold tablet ingredients together and improve how the medicine flows during manufacturing.
  • UNII 5Y0974F5PW
    Hydroxypropyl cellulose is a plant-derived thickener and binder made by chemically treating cellulose. In medicines, it helps hold tablets together, thickens liquids, and can form a protective coating on capsules.
  • UNII B1QE5P712K
    Hypromellose 2208 is a plant-derived thickening agent that dissolves in water. It's used as a binder to help hold tablet ingredients together and as a coating on pills to control how quickly the medicine releases in your body.
  • UNII 0HO1H52958
    Hypromellose 2910 is a plant-derived cellulose that forms a protective coating around tablets or capsules. It slows how fast the medicine releases, helps protect the active ingredient, and improves how the product looks.
  • UNII 70097M6I30
    Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
  • UNII 3OWL53L36A
    A natural sugar alcohol derived from seaweed or synthesized in the lab. It's used as a filler to add bulk, a sweetener in sugar-free formulas, and a disintegrant to help tablets break apart in the stomach.
  • UNII OP1R32D61U
    Microcrystalline cellulose is a purified form of cellulose, a natural fiber from plant sources. It acts as a binder and filler in tablets and capsules, helping hold ingredients together and give the medicine its shape and size.
  • UNII U076Q6Q621
    Polyethylene glycol 1000 is a synthetic compound made from ethylene oxide. It serves as a solvent, lubricant, and humectant in medicines, helping dissolve active ingredients and improve how the product flows and feels.
  • UNII ETJ7Z6XBU4
    Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
  • UNII 5856J3G2A2
    A starch-based powder made from potatoes and processed with sodium. It acts as a disintegrant, helping the tablet or capsule break apart quickly in the stomach so the medicine can be absorbed.
  • UNII O8232NY3SJ
    A plant-based carbohydrate derived from corn kernels. It acts as a filler to add bulk, a binder to hold ingredients together, and a disintegrant to help the tablet break apart in your stomach for absorption.

12 inactive ingredients listed in the exact product block matched to this NDC.

Where does this data come from?
Data sourced from official FDA Structured Product Labeling (SPL) via DailyMed — ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.

Inactive ingredient FAQ

Are inactive ingredients the same for every manufacturer?
No. Inactive ingredients can differ by manufacturer, dosage form, strength, and package / product version.
Why might an inactive ingredient be missing?
Some SPLs do not provide a complete structured inactive-ingredient list, and older or unusual labels may only include the information in narrative text.
Can inactive ingredients matter?
Yes. They can matter for allergies, intolerances, dyes, gluten / lactose concerns, preservatives, and formulation differences — but confirm with a pharmacist or the manufacturer when it’s clinically important.

Manufacturer & labeler

LabelerGolden State Medical Supply, Inc.
Application holderSTRIDES PHARMA INTERNATIONAL AG
FDA applicationANDA212670 (ANDA)
Labeler code51407
First marketedDec 2019
Product typeHuman Prescription Drug
Portfolio671 products on file
The labeler markets the product; the application holder owns the FDA approval. They’re often the same company but can differ (e.g. a repackager or an authorized generic). A mailing address / phone appears here when the manufacturer includes it in the product’s FDA label (not all do).
Where does this data come from?
Labeler, application holder and registered establishment from the FDA openFDA NDC Directory and Drugs@FDA; address/contact from the product’s FDA label.

Full prescribing information FDA SPL

The complete FDA label for this product — the official prescribing information, verbatim, section by section. Jump with a chip, search within the label, or expand everything.
🎯 Indications and Usage ⏱️ Dosage and Administration 💊 Dosage Forms and Strengths ⛔ Contraindications ⚠️ Warnings and Cautions 🤒 Adverse Reactions 🔄 Drug Interactions 👥 Use in Specific Populations 🆘 Overdosage 🧬 Clinical Pharmacology 📦 How Supplied / Storage and Handling 📋 Description 💬 Information for Patients
🎯 Indications and Usage 98 words ▾

1 INDICATIONS AND USAGE Zileuton extended-release tablets are indicated for the prophylaxis and chronic treatment of asthma in adults and children 12 years of age and older. Zileuton extended-release tablets are not indicated for use in the reversal of bronchospasm in acute asthma attacks. Therapy with zileuton extended-release tablets can be continued during acute exacerbations of asthma.

Zileuton extended-release tablets are a leukotriene synthesis inhibitor indicated for the prophylaxis and chronic treatment of asthma in adults and children 12 years of age and older. (1) Do not use zileuton extended-release tablets to treat an acute asthma attack. (1)

⏱️ Dosage and Administration 161 words ▾

2 DOSAGE AND ADMINISTRATION The recommended dosage of Zileuton extended-release tablets for the treatment of patients with asthma is two 600 mg extended-release tablets twice daily, within one hour after morning and evening meals, for a total daily dose of 2400 mg. Tablets should not be chewed, cut or crushed. If a dose is missed, the patient should take the next dose at the scheduled time and not double the dose.

Assess hepatic function enzymes prior to initiation of zileuton extended-release tablets and periodically during treatment [ see Contraindications (4), Warnings and Precautions (5), and Use in Specific Populations (8.7) ]. Adults and children 12 years of age and older: The recommended dose of zileuton extended-release tablets is two 600 mg extended-release tablets twice daily, within one hour after morning and evening meals, for a total daily dose of 2400 mg. (2) Monitoring: Assess hepatic function enzymes prior to initiation of zileuton extended-release tablets and monitor periodically during treatment.

(2, 5.1)

💊 Dosage Forms and Strengths 14 words ▾

3 DOSAGE FORMS AND STRENGTHS Extended-release tablets, 600 mg. Extended-release tablets: 600 mg. (3)

⛔ Contraindications 101 words ▾

4 CONTRAINDICATIONS The use of Zileuton extended-release tablets is contraindicated in patients with: Active liver disease or persistent hepatic function enzyme elevations greater than or equal to 3 times the upper limit of normal (≥3×ULN) [see Warnings and Precautions (5), and Use in Specific Populations (8.7)] . A history of allergic reaction to zileuton or any of the ingredients of zileuton extended-release tablets (e.g., rash, eosinophilia, etc.). Active liver disease or persistent hepatic function enzyme elevations ≥3 times the upper limit of normal.

(4, 5.1) History of allergic reaction to zileuton or any of the ingredients of zileuton extended-release tablets. (4)

⚠️ Warnings and Cautions ~2 min read ▾

5 WARNINGS AND PRECAUTIONS Hepatotoxicity: Elevations of one or more hepatic function enzymes and bilirubin may occur with zileuton extended-release tablets. Assess hepatic function enzymes prior to initiation of zileuton extended-release tablets, monthly for the first 3 months, every 2 to 3 months for the remainder of the first year, and periodically thereafter. Use zileuton extended-release tablets with caution in patients who consume substantial quantities of alcohol and/or have a history of liver disease.

(5.1) Neuropsychiatric Events : Neuropsychiatric events, including sleep disorders and behavior changes, may occur with zileuton extended-release tablets. Instruct patients to be alert for neuropsychiatric events. Evaluate the risks and benefits of continuing treatment with zileuton extended-release tablets if such events occur.

(5.2)

5.1Hepatotoxicity Elevations of one or more hepatic function enzymes and bilirubin may occur during zileuton extended-release tablets therapy. These laboratory abnormalities may progress to clinically significant liver injury, remain unchanged, or resolve with continued treatment, usually within three weeks. The ALT (SGPT) test is considered the most sensitive indicator of liver injury for zileuton extended-release tablets.

Assess hepatic function enzymes prior to initiation of, and during therapy with, zileuton extended- release tablets. Assess serum ALT before treatment begins, once a month for the first 3 months, every 2 to 3 months for the remainder of the first year, and periodically thereafter for patients receiving long-term zileuton extended-release tablets therapy. If clinical signs and/or symptoms of liver dysfunction develop (e.g., right upper quadrant pain, nausea, fatigue, lethargy, pruritus, jaundice, or "flu-like" symptoms) or transaminase elevations ≥5×ULN occur, discontinue zileuton extended-release tablets and follow hepatic function enzymes until normal.

In controlled and open-label clinical studies involving more than 5000 patients treated with zileuton immediate-release tablets, the overall rate of ALT elevation ≥3×ULN was 3.2%. In these trials, one patient developed symptomatic hepatitis with jaundice, which resolved upon discontinuation of therapy. An additional 3 patients with transaminase elevations developed mild hyperbilirubinemia that was less than 3×ULN.

There was no evidence of hypersensitivity or other alternative etiologies for these findings. Since treatment with zileuton extended-release tablets may result in increased hepatic function enzymes and liver injury, zileuton extended-release tablets should be used with caution in patients who consume substantial quantities of alcohol and/or have a past history of liver disease.

5.2Neuropsychiatric Events Neuropsychiatric events have been reported in adult and adolescent patients taking zileuton, the active ingredient in zileuton extended-release tablets and zileuton immediate-release tablets. Post- marketing reports with zileuton include sleep disorders and behavior changes. The clinical details of some post-marketing reports involving zileuton appear consistent with a drug-induced effect.

Patients and prescribers should be alert for neuropsychiatric events. Patients should be instructed to notify their prescriber if these changes occur. Prescribers should carefully evaluate the risks and benefits of continuing treatment with zileuton extended-release tablets if such events occur [see Adverse Reactions (6.3)].

🤒 Adverse Reactions ~3 min read ▾

6 ADVERSE REACTIONS Hepatotoxicity: Elevations of one or more hepatic function enzymes and bilirubin may occur during zileuton extended-release tablets therapy [see Warnings and Precautions (5)]. The most commonly occurring adverse reactions (≥5%) with zileuton extended-release tablets are sinusitis, nausea, and pharyngolaryngeal pain. Most common adverse reactions (≥5%) included: sinusitis, nausea, and pharyngolaryngeal pain.

(6.1) To report SUSPECTED ADVERSE REACTIONS, contact Strides Pharma Inc at 1-877-244-9825 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

6.1Short-Term Clinical Studies Experience The safety data described below reflect exposure to zileuton extended-release tablets in 199 patients for 12 weeks duration. In a 12-week, randomized, double-blind, placebo-controlled trial in adults and adolescents 12 years of age and older with asthma, patients received zileuton extended-release tablets two 600 mg tablets (n=199) or placebo (n=198) twice daily by mouth. Eighty-three percent of patients were white, 48% were male, and the mean age was 34 years.

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. The most commonly reported adverse reactions (occurring at a frequency of ≥5%) in zileuton extended-release tablets-treated patients and at a frequency greater than placebo-treated patients are reflected in Table 1 . Table 1.

Adverse Reactions with ≥5% Incidence in a 12-Week Placebo-Controlled Trial in Patients with Asthma. Adverse Reaction Zileuton Extended-Release Tablets 600 mg 2 Tablets Twice Daily N=199 n (%) Placebo 2 Tablets Twice Daily N=198 n (%) Sinusitis 13 (6.5) 8 (4.0) Nausea 10 (5.0) 3 (1.5) Pharyngolaryngeal pain 10 (5.0) 8 (4.0) Less common adverse reactions occurring at a frequency ≥1% and more often in the zileuton extended-release tablets group than in the placebo group included gastrointestinal disorders (upper abdominal pain, diarrhea, dyspepsia, vomiting), rash, hypersensitivity, and hepatotoxicity.

There were no differences in the incidence of adverse reactions based upon gender. The clinical trials did not include sufficient numbers of patients <18 years of age or non-Caucasians to determine whether there is any difference in adverse reactions based upon age or race. Hepatotoxicity In the 12-week placebo-controlled trial, the incidence of ALT elevations (≥3×ULN) was 2.5% (5 of 199) in the zileuton extended-release tablets group, compared to 0.5% (1 of 198) in the placebo group.

In the zileuton extended-release tablets group, the majority of ALT elevations (60%) occurred in the first month of treatment, and in 2 of the 5 patients in the zileuton extended-release tablets group, ALT elevations were detected 14 days after completion of the 3-month study treatment. The levels returned to <2×ULN or normal within 9 and 12 days, respectively. The ALT elevations in the other 3 patients were observed to return to <2×ULN or normal within 15, 19, and 31 days after zileuton extended-release tablets discontinuation.

There appeared to be no clinically relevant relationship between the time of onset and the magnitude of the first elevation or the magnitude of first elevation and time to resolution. The hepatic function enzyme elevations attributed to zileuton extended-release tablets did not result in any cases of jaundice, development of chronic liver disease, or death in this clinical trial.

6.2Long-Term Clinical Studies Experience The safety of zileuton extended-release tablets was evaluated in one 6-month, randomized, double-blind, placebo-controlled clinical trial in adults and adolescents 12 years of age and older with asthma. Patients received two 600 mg zileuton extended-release tablets (n=619) or placebo (n=307) twice daily by mouth along with usual asthma care. Eighty-six percent of pat…

🔄 Drug Interactions ~2 min read ▾

7 DRUG INTERACTIONS The following study results were obtained using zileuton immediate-release tablets but the conclusions also apply to zileuton extended-release tablets. Zileuton increases theophylline levels. Reduce theophylline dose and monitor levels.

(7.1) Zileuton increases warfarin levels. Monitor prothrombin time and adjust warfarin dose accordingly. (7.2) Zileuton increases propranolol levels and beta-blocker activity.

Monitor appropriately. (7.3)

7.1Theophylline In a drug-interaction study in 16 healthy subjects, coadministration of multiple doses of zileuton immediate-release tablets (800 mg every 12 hours) and theophylline (200 mg every 6 hours) for 5 days resulted in a significant decrease (approximately 50%) in steady-state clearance of theophylline, an approximate doubling of theophylline AUC, and an increase in theophylline C max (by 73%). The elimination half-life of theophylline was increased by 24%. Also, during coadministration, theophylline-related adverse reactions were observed more frequently than after theophylline alone.

Upon initiation of zileuton extended-release tablets in patients receiving theophylline, the theophylline dosage should be reduced by approximately one-half and plasma theophylline concentrations monitored. Similarly, when initiating therapy with theophylline in a patient receiving zileuton extended-release tablets, the maintenance dose and/or dosing interval of theophylline should be adjusted accordingly and guided by serum theophylline determinations.

7.2Warfarin Concomitant administration of multiple doses of zileuton immediate-release tablets (600 mg every 6 hours) and warfarin (fixed daily dose obtained by titration in each subject) to 30 healthy male subjects resulted in a 15% decrease in R-warfarin clearance and an increase in AUC of 22%. The pharmacokinetics of S-warfarin were not affected. These pharmacokinetic changes were accompanied by a clinically significant increase in prothrombin times.

Monitoring of prothrombin time, or other suitable coagulation tests, with the appropriate dose titration of warfarin is recommended in patients receiving concomitant zileuton extended-release tablets and warfarin therapy.

7.3Propranolol Coadministration of zileuton immediate-release tablets and propranolol results in a significant increase in propranolol concentrations. Administration of a single 80 mg dose of propranolol in 16 healthy male subjects who received zileuton immediate-release tablets 600 mg every 6 hours for 5 days resulted in a 42% decrease in propranolol clearance. This resulted in an increase in propranolol C max , AUC, and elimination half-life by 52%, 104%, and 25%, respectively.

There was an increase in β-blockade as shown by a decrease in heart rate associated with the coadministration of these drugs. Patients concomitantly on zileuton extended-release tablets and propranolol should be closely monitored and the dose of propranolol reduced as necessary. No formal drug-drug interaction studies between zileuton and other beta-adrenergic blocking agents (i.e., β-blockers) have been conducted.

It is reasonable to employ appropriate clinical monitoring when these drugs are coadministered with zileuton extended-release tablets.

7.4Other Concomitant Drug Therapy Drug-drug interaction studies conducted in healthy subjects between zileuton immediate-release tablets and prednisone and ethinyl estradiol (oral contraceptive), drugs known to be metabolized by the CYP3A4 isoenzyme, have shown no significant interaction. However, no formal drug-drug interaction studies between zileuton and CYP3A4 inhibitors, such as ketaconazole, have been conducted. It is reasonable to employ appropriate clinical monitoring when these drugs are coadministered with zileuton extended-release tablets.

Drug-drug interaction studies in healthy subjects have been conducted with zileuton immediate-release tablets and digoxin, phenytoin, sulfasalazine, and naproxen. There was no significant interactio…

👥 Use in Specific Populations ~3 min read ▾

8 USE IN SPECIFIC POPULATIONS Information on specific populations is based on studies conducted with zileuton immediate-release tablets and is applicable to zileuton extended-release tablets. Hepatic Impairment: Zileuton extended-release tablets are contraindicated in patients with active liver disease and in patients with elevated hepatic function enzymes ≥3 times the upper limit of normal. (4, 5, 8.7) See 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labelling.

8.1Pregnancy Risk Summary There are no adequate human data on zileuton extended-release tablets use in pregnant women to inform a drug associated risk. In animal studies, oral administration of zileuton to pregnant rats and rabbits during organogenesis produced adverse developmental outcomes. Structural abnormalities (cleft palate) were observed in rabbits at a dose similar to the maximum recommended human daily oral dose (MRHD), and alterations to growth (reduced fetal body weight and increased skeletal variations) were observed in rats at maternal plasma exposures 20 times greater than at the MRHD [see Data ].

In a pre- and post-natal development study, oral administration of zileuton to pregnant rats from organogenesis through weaning at maternal plasma exposures 20 times greater than the MRHD resulted in reduced pup survival and body weights. Zileuton and/or its metabolites cross the placental barrier of rats; therefore, zileuton extended-release tablets may be transmitted from the mother to the developing fetus. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to asthma medications during pregnancy. For more information, contact the MothersToBaby Pregnancy Studies conducted by the Organization of Teratology Information Specialists at 1-877- 311-8972 or visit http://mothertobaby.org/pregnancy-studies/. Data Animal Data In a fertility and general reproductive performance study in rats, 0, 15, 75, 150 or 300 mg/kg/day zileuton was administered orally to male and female rats.

The treated males were dosed daily for 100 days prior to mating with the treated females and 80 days prior to mating with untreated females, and throughout the mating periods. The treated females were dosed for 14 days before mating with untreated males and dosing continued throughout gestation, and in 1/3 of the females through parturition and lactation period. Maternal body weight gain was reduced at 150 and 300 mg/kg/day groups (9 to12% differences in body weight relative to controls).

During fetal evaluation, zileuton produced lower litter size (7.1 pup/dams at 300 mg/kg/day vs. 9.6 pup/dams at 150 mg/kg/day vs. 13.5 pup/dams in control group), lower fetal weights (-9%), decreased viable fetuses, and increased in unossification of fetal skeletal structure at 300 mg/kg at exposures greater than 20 times the MRHD (on an AUC basis with data obtained from the comparable doses of 3-month general toxicity study).

There were no embryofetal effects at 150 mg/kg/day. During post-natal development evaluation, zileuton produced decrease in pup viability (-16% at 150 mg/kg/day and -43.5% at 300 mg/kg/day on lactation Day 4) as well as depression of body weight gain in pups at ≥ 150 mg/kg/day at exposures close to 20 times the MRHD (on an AUC basis with data obtained from the comparable doses of 1-year general toxicity study). Observations of lower pup weight and survival rate at 300 mg/kg/day group were confirmed in a peri- & post-natal study administered with the same dose levels in pregnant rats.

In a teratology study in pregnant rabbits, 0, 15, 50 or 150 mg/kg/day zileuton was administered orally to pregnant animals during organogenesis. Cleft palate was noted in three of 118 (2.5%) rabbit fetuses (or 2 of 17 litters) at 150 mg/kg/day. Addit…

🆘 Overdosage 104 words ▾

10 OVERDOSAGE Human experience of acute overdose with zileuton is limited. A patient in a clinical study took between 6.6 and 9.0 grams of zileuton immediate-release tablets in a single dose. Vomiting was induced and the patient recovered without sequelae.

Zileuton is not removed by dialysis. Should an overdose occur, the patient should be treated symptomatically and supportive measures instituted as required. If indicated, elimination of unabsorbed drug should be achieved by emesis or gastric lavage; usual precautions should be observed to maintain the airway.

A Certified Poison Control Center should be consulted for up-to-date information on management of overdose with zileuton extended-release tablets.

🧬 Clinical Pharmacology ~3 min read ▾

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Zileuton is an inhibitor of 5-lipoxygenase and thus inhibits leukotriene (LTB 4 , LTC 4 , LTD 4 and LTE 4 ) formation. Both the R(+) and S(-) enantiomers are pharmacologically active as 5-lipoxygenase inhibitors in in vitro and in vivo systems. Leukotrienes are substances that induce numerous biological effects including augmentation of neutrophil and eosinophil migration, neutrophil and monocyte aggregation, leukocyte adhesion, increased capillary permeability, and smooth muscle contraction.

These effects contribute to inflammation, edema, mucus secretion, and bronchoconstriction in the airways of asthmatic patients. LTB 4 , a chemoattractant for neutrophils and eosinophils, and cysteinyl leukotrienes (LTC 4 , LTD 4 , LTE 4 ) can be measured in a number of biological fluids including bronchoalveolar lavage fluid (BALF), blood, urine and sputum from asthmatic patients. Zileuton is an orally active inhibitor of ex vivo LTB 4 formation in several species, including mice, rats, rabbits, dogs, sheep, and monkeys.

Zileuton inhibits arachidonic acid-induced ear edema in mice, neutrophil migration in mice in response to polyacrylamide gel, and eosinophil migration into the lungs of antigen-challenged sheep. In a mouse model of allergic inflammation, zileuton inhibited neutrophil and eosinophil influx, reduced the levels of multiple cytokines in the BALF, and reduced serum IgE levels. Zileuton inhibits leukotriene-dependent smooth muscle contractions in vitro in guinea pig and human airways.

The compound inhibits leukotriene-dependent bronchospasm in antigen and arachidonic acid-challenged guinea pigs. In antigen-challenged sheep, zileuton inhibits late-phase bronchoconstriction and airway hyperreactivity. The clinical relevance of these findings is unknown.

12.2Pharmacodynamics Zileuton is an orally active inhibitor of ex vivo LTB 4 formation in humans. The inhibition of LTB 4 formation in whole blood is directly related to zileuton plasma levels. In patients with asthma, the IC 50 is estimated to be 0.46 μg/mL, and maximum inhibition ≥80% is reached at a zileuton concentration of 2 μg/mL.

In patients with asthma receiving zileuton immediate-release tablets 600 mg four times daily, peak plasma levels averaging 5.9 μg/mL were associated with a mean LTB 4 inhibition of 98%. Zileuton inhibits the synthesis of cysteinyl leukotrienes as demonstrated by reduced urinary LTE 4 levels.

12.3Pharmacokinetics Information on the pharmacokinetics of zileuton following the administration of zileuton immediate-release tablets is available in healthy subjects. The results of two clinical pharmacology studies using zileuton extended-release tablets are described below. Absorption A three-way crossover study was conducted in healthy male and female subjects (n=23) with a mean age of 33 (range 20 to 55) following single dose of 1200 mg (2 x 600 mg) zileuton extended-release tablets under fasted and fed conditions, and two doses of 600 mg zileuton immediate-release tablets every 6 hours under fasted conditions.

Food increased the peak mean plasma concentrations (C max ) and the mean extent of absorption (AUC) of zileuton extended-release tablets by 18 and 34%, respectively, and prolonged T max from 2.1 hours to 4.3 hours. The relative bioavailability of zileuton extended-release tablets to zileuton immediate-release tablets with respect to C max and AUC under fasted conditions were 0.39 (90% CI: 0.36, 0.43) and 0.57 (90% CI: 0.52, 0.62), respectively. Similarly, relative bioavailability of zileuton extended-release tablets to zileuton immediate-release tablets with respect to C max and AUC under fed conditions were 0.45 (90% CI: 0.41, 0.49) and 0.76 (90% CI: 0.70, 0.83), respectively.

A three-way crossover study was conducted in healthy male and female subjects (n=24) with a mean age of 35 (range 19 to 56) following multiple doses of 1200 mg (2 × 600 mg) zileuton extended-release tablets administered ev…

📦 How Supplied / Storage and Handling 68 words ▾

16 HOW SUPPLIED/STORAGE AND HANDLING Zileuton Extended-Release Tablets, 600 mg are oblong, film-coated tablets with one red layer between two white layers, debossed on one side with "P723" and plain on other side; they are available in bottles of 120 tablets (NDC 51407-741-12). Store between 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. Protect from light.

📋 Description 188 words ▾

11 DESCRIPTION Zileuton is an orally active inhibitor of 5-lipoxygenase, the enzyme that catalyzes the formation of leukotrienes from arachidonic acid. Zileuton has the chemical name (±)-1-(1-Benzo[b]thien-2-ylethyl)-1-hydroxyurea and the following chemical structure: Zileuton has the molecular formula C 11 H 12 N 2 O 2 S and a molecular weight of 236.29. It is a racemic mixture (50:50) of R(+) and S(-) enantiomers.

Zileuton is a practically odorless, white to off-white powder that is soluble in methanol and ethanol, slightly soluble in acetonitrile, and practically insoluble in water and hexane. The melting point ranges from 144.2° to 145.2°C. Zileuton extended-release tablets for oral administration are triple-layer tablets comprised of an immediate-release layer, a middle (barrier) layer, and an extended-release layer.

Zileuton extended-release tablets are oblong, film-coated tablets with one red layer between two white layers, debossed on one side with "P723" and plain on other side. Each tablet contains 600 mg of zileuton and the following inactive ingredients: colloidal silicon dioxide, glyceryl behenate, hydroxypropyl cellulose, hydroxypropyl methylcellulose, hypromellose, iron oxide red, magnesium stearate, mannitol, microcrystalline cellulose, polyethylene glycol, pregelatinized starch and sodium starch glycolate. Chemical structure of zileuton

💬 Information for Patients ~3 min read ▾

17 PATIENT COUNSELING INFORMATION

17.1Information for Patients Patients should be told that: Zileuton extended-release tablets are indicated for the chronic treatment of asthma and should be taken regularly as prescribed, even during symptom-free periods. Zileuton extended-release tablets are a leukotriene synthesis inhibitor which works by inhibiting the formation of leukotrienes. Zileuton extended-release tablets should be taken within one hour after morning and evening meals.

Zileuton extended-release tablets should not be cut, chewed or crushed. Zileuton extended-release tablets are not a bronchodilator and should not be used to treat acute episodes of asthma. When taking zileuton extended-release tablets, they should not decrease the dose or stop taking any other antiasthma medications unless instructed by a health care provider.

If a dose is missed, they should take the next dose at the scheduled time and not double the dose. While using zileuton extended-release tablets, medical attention should be sought if short-acting bronchodilators are needed more often than usual, or if more than the maximum number of inhalations of short-acting bronchodilator treatment prescribed for a 24-hour period are needed. The most serious side effect of zileuton extended-release tablets is potential elevation of liver enzymes (in 2% of patients) and that, while taking zileuton extended-release tablets, they must return for liver enzyme test monitoring on a regular basis.

If they experience signs and/or symptoms of liver dysfunction (e.g., right upper quadrant pain, nausea, fatigue, lethargy, pruritus, jaundice, or "flu-like" symptoms), they should contact their health care provider immediately. Patients should be instructed to notify their healthcare provider if neuropsychiatric events occur while using zileuton extended-release tablets. Zileuton extended-release tablets can interact with other drugs and that, while taking zileuton extended-release tablets, they should consult their health care provider before starting or stopping any prescription or non-prescription medicines.

A patient leaflet is included with the tablets.

17.2FDA-Approved Patient Labeling PATIENT INFORMATION Zileuton (zi· leu· ton) Extended-Release Tablets Read the Patient Information that comes with zileuton extended-release tablets carefully before you start taking them and read it each time you get a refill. There may be new information. This leaflet does not take the place of talking with your health care provider about your medical condition or your treatment.

What are zileuton extended-release tablets? Zileuton extended-release tablets are a medicine that is used to prevent asthma attacks and for long-term management of asthma in adults and children 12 years of age and older. Zileuton extended-release tablets blocks the production of leukotrienes.

Leukotrienes are substances that may contribute to your asthma. Zileuton extended-release tablets are not a rescue medicine (it is not a bronchodilator) and should not be used if you need relief right away for an asthma attack. Who should not take zileuton extended-release tablets?

Do not take zileuton extended-release tablets if you have: active liver disease or repeated blood tests showing elevated liver enzymes (substances released by the liver). ever had an allergic reaction to zileuton extended-release tablets or any of the ingredients in zileuton extended-release tablets. What should I tell my health care provider before taking zileuton extended-release tablets? Zileuton extended-release tablets may not be right for you.

Tell your health care provider if you: have ever had liver problems, including hepatitis, jaundice (yellow eyes or skin), or dark urine. drink alcohol. Tell your health care provider how much and how often you drink alcohol. have difficulty swallowing pills. are pregnant or planning to become pregnant. It is not known if zileuton extended-release tablets will harm your unborn baby.

Do not take zi…

Source: FDA Structured Product Labeling, mirrored from DailyMed / openFDA. Prefer the government’s original formatting? View this label on DailyMed ↗

Medicare Part D spend CMS · PART D · 2026 (Q1)

Medicare Part D (outpatient prescription) spending for Zileuton ER (matched by generic name) — the program that covers self-administered drugs. 4 manufacturers.
⚠️ Drug-level data: CMS publishes Part D spending by drug, not by NDC — these figures combine every manufacturer, strength and package size sold under the name Zileuton ER. CMS lists 2 products for this generic; we show the highest-spend one. That’s a different level of aggregation than the Medicaid card above, which is specific to this exact 11-digit NDC (pack size included), so the two aren’t directly comparable.
Period
Total Part D spend
$8.67M
Claims incl. refills
3.7K
Beneficiaries
1.6K
Spend / beneficiary
$5,358.09
Spend / claim
$2,324.85
Trend by period
💵 About the dollar figures: spending is what Part D plans paid before confidential manufacturer rebates, so the program’s real net cost is lower. A blank patient count means fewer than 11 people — CMS hides counts that small to protect privacy. Source: CMS Medicare Quarterly Part D Spending by Drug (data.cms.gov), updated quarterly.

Reported adverse events (FAERS)

Read carefully: FAERS reports are voluntary and unverified. Counts are not incidence, do not establish causation, are subject to reporting bias, and cannot be used to compare one drug to another. Shown for signal context only. Reports for ZILEUTON — the ingredient across all brands.

Top reported reactions

Asthma76
Dyspnoea52
Nausea40
Pneumonia33
Cough31
Fatigue30
Headache26

Age at onset

Adolescent2
Adult84
Elderly35

Reporter sex

641 reports
Male · 27%
Female · 73%

Serious outcomes

Hospitalization164
Life-threatening22
Death22
Disabling10
Reports over time (by year) — tap or hover for the count & year
2019 2021 2023 2026 49 0
Most recent year is provisional (FAERS lags ~3 months).
Where does this data come from?
Adverse-event reports from the FDA Adverse Event Reporting System (FAERS) via openFDA. FAERS reports are voluntary and unverified — counts are not incidence and don’t establish causation.

About this NDC listing & data coverage

Finished prescription product
What data is (and isn’t) available for this NDC — tap to expand
NDC identity (package / product / labeler codes) ✓ Available
Labeler ✓ Available
Product & package description ✓ Available
Marketing category & status ✓ Available
Active ingredient / dosage form / route ✓ Available
FDA label (SPL via DailyMed) ✓ Available
Package photos ✓ Available
Inactive ingredients (structured) ✓ Available
NADAC pharmacy acquisition price (CMS) — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey.
Orange Book / therapeutic-equivalence data ✓ Available
HCPCS J-code billing crosswalk — Not published for this NDC Most self-administered / retail products have no J-code — that is normal.
Medicaid utilization (CMS SDUD) — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold.
“Not published” reflects what the public FDA / CMS / NLM sources provide for this exact package code — it is a property of the data feeds, not a judgment about the product.

Questions about this listing

Why is there no price listed?
The pricing shown on our NDC pages comes from CMS NADAC, a voluntary survey of retail community pharmacy invoices. CMS does not publish a NADAC for every NDC — packages outside the retail survey (institutional and hospital products, bulk packages, discontinued items, and many OTC items) may never receive one. A missing price reflects the survey's scope, not this product's actual cost, and does not mean the product is free or unavailable.
Is the NDC printed on the package the same as the 11-digit billing NDC?
Yes, they identify this exact package in different formats. The form printed on the packaging and shown on DailyMed is the one the FDA registered. Insurance claims use a fixed 11-digit 5-4-2 format, so the short segment is padded with a leading zero and the dashes are dropped. The Identity section at the top of this page lists each form of this code.
Is this package still being marketed?
Yes, per the latest FDA NDC Directory data on this page: this package is listed as actively marketed, with no marketing end date reported by Golden State Medical Supply, Inc.. Listing status can change — the directory data on this page refreshes weekly.
Who lists this product with the FDA?
Golden State Medical Supply, Inc. is the labeler of record for this NDC — the company under whose FDA-assigned code the package is listed. The labeler may be the manufacturer itself or a distributor marketing the product under its own code.
Do I need a prescription for this product?
This NDC is listed with FDA as a prescription product, so it is dispensed under a prescriber's order. Your pharmacist can tell you whether any over-the-counter forms of the same medication exist.
This page identifies an FDA-listed package (the NDC) and reports public regulatory and pricing data about the listing. It is reference information, not a medical recommendation — talk to your pharmacist or prescriber about your own medication.
Where does this data come from?
Listing facts (marketing category, packager status, marketing dates) from the FDA openFDA NDC Directory; label availability from DailyMed; pricing coverage from CMS NADAC; equivalence scope from the FDA Orange Book.
← 51407-0740-05 · Golden 51407-0742-10 · Golden →
For educational and professional reference only — not medical advice. Pricing reflects published NADAC and CMS ASP (free public data) and may differ from your acquisition cost; always verify before billing or dispensing.