Zileuton 600 mg Tablet, Extended Release, 120-count — NDC 64980-206-12 (Billing 64980-0206-12)
This is a package of 120 tablets of Zileuton 600 mg Tablet, Extended Release from Rising Pharma Holdings, Inc., marketed since Mar 2017 and currently FDA-listed; retail pharmacies pay about $2.05 per tablet (NADAC). It is this product's only package size.
Identity & classification
Regulatory identifiers FDA, NLM and CMS codes for this package
Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification
- GSN (GCN sequence number): 063062
- GCN: 98822
- GPI-14 (Medi-Span): 44504085007420
- HICL (First Databank): 012321
- AHFS class code: 48:10.24.00
- RxCUI (RxNorm): 730834
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 1, 2026
- FDA label on DailyMed · label index refreshed Oct 1, 2026
- RxNorm (NLM RxNav) · catalog refreshed Oct 1, 2026
- Medi-Span GPI (licensed)
- First Databank (licensed) · refreshed Oct 1, 2026
RxNorm drug class
This medicine belongs to the 5-Lipoxygenase Inhibitor class.
Where does this data come from?
- RxClass (NLM) · catalog refreshed Oct 1, 2026
Clinical
- 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?
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Zileuton — tap one for details:
Where does this data come from?
- MedlinePlus (NLM) · refreshed Oct 1, 2026
- FDA label on DailyMed · label index refreshed Oct 1, 2026
Ask a licensed pharmacist directly — free, answered by our team.
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 system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $2.049 | $245.92 / 120 tablets |
| Medicaid paysCMS SDUD · 12 mo | $3.42 | $410.04 / 120 tablets |
| Medicare drug plans payPart D · Q2 2026 | $17.64 | $2,116.57 / 120 tablets |
Where does this data come from?
- CMS NADAC weekly file · file of Sep 30, 2026
- CMS ASP pricing files · refreshed Sep 20, 2026
- CMS Medicaid State Drug Utilization Data · through Q1 2026
- CMS Part D plan pricing files · refreshed Sep 24, 2026
- VA National Acquisition Center price file
Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Marketing end | Status |
|---|---|---|---|---|
| 64980-0206-12 You're viewing this Main listing | 120 TABLET, EXTENDED RELEASE in 1 BOTTLE | 2017-03-21 | — | Active |
Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price 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 mgthis 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 mg 51407-0741-12 | Golden | 120 tablets | — | AB | FDA listed | — |
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 1, 2026
- FDA Orange Book · refreshed Sep 3, 2026
- CMS NADAC weekly file · file of Sep 30, 2026
Availability & generic status
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?
- FDA Orange Book · refreshed Sep 3, 2026
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.
Where does this data come from?
IACT rows and label-wide narrative are kept separate; availability and product-level specificity depend on the submitted label.- FDA label on DailyMed · label index refreshed Oct 1, 2026
- FDA openFDA NDC Directory · synced Oct 1, 2026
Inactive ingredient FAQ
Are inactive ingredients the same for every manufacturer?
Why might an inactive ingredient be missing?
Can inactive ingredients matter?
Manufacturer & labeler
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 1, 2026
- Drugs@FDA
Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE Zileuton Extended-Release Tablets is 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 is 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 ▾
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 ▾
3 DOSAGE FORMS AND STRENGTHS Extended-release tablets, 600 mg. Extended-Release tablets: 600 mg. ( 3 )
⛔ Contraindications ▾
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 ▾
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 2-3 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 2-3 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) ].
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, Zil… [Excerpted — this section continues on DailyMed.]
🤒 Adverse Reactions ▾
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 Rising Pharma Holdings, Inc. at 1-844-874-7464 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 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… [Excerpted — this section continues on DailyMed.]
🔄 Drug Interactions ▾
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, co-administration 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 co-administration, 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 Co-administration 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 co-administration 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 co-administered 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 co-administered 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 significan… [Excerpted — this section continues on DailyMed.]
👥 Use in Specific Populations ▾
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 is 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 )
8.1Pregnancy Risk Summary: There are no adequate human data on zileuton 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 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 2-4% and 15-20%, 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 (9-12% 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. Additionally, two fetuses (1.7%) had domed head and two fetuses (1.7%) had hydrocephalus also at 150 mg/kg/day which was equivalent to t… [Excerpted — this section continues on DailyMed.]
🆘 Overdosage ▾
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-todate information on management of overdose with Zileuton Extended-Release Tablets. The oral minimum lethal doses in mice and rats were 500-4000 and 300-1000 mg/kg, respectively (providing greater than 3 and 9 times the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose, respectively). In dogs, at an oral dose of 1000 mg/kg (providing in excess of 12 times the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose) no deaths occurred but nephritis was reported.
🧬 Clinical Pharmacology ▾
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 20-55) following single dose of 1200 mg (2 × 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 19-56) following multiple doses of 1200 mg (2 × 600 mg) Zileuton Extended-Release Tablets administered every 12… [Excerpted — this section continues on DailyMed.]
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING Zileuton Extended-Release Tablets are yellow colored, oval shaped, biconvex tablets debossed with “656” on one side and “P” on the other side; they are supplied in bottles of 120 tablets (NDC 64980-206-12). Store between 20 to 25°C (68 to 77°F); excursions permitted to 15-30°C (59 to 86°F) [see USP Controlled Room Temperature]. Protect from light.
📋 Description ▾
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, crystalline 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°C to 145.2°C. Zileuton Extended-Release Tablets for oral administration are bi-layer tablets comprising of an immediate-release layer and extended-release layer.
Zileuton Extended-Release Tablets are oval shaped, biconvex tablets debossed with “656” on one side and “P” on the other side. Each tablet contains 600 mg of zileuton and the following inactive ingredients: colloidal silicon dioxide, crospovidone, hydroxypropyl cellulose, hypromellose, magnesium stearate, mannitol, microcrystalline cellulose, partially pregelatinized maize starch, polyethylene glycol 400, sodium lauryl sulfate, sodium starch glycolate, titanium dioxide, yellow iron oxide. structure
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION
17.1Information for Patients Patients should be told that: Zileuton Extended-Release Tablets is indicated for the chronic treatment of asthma and should be taken regularly as prescribed, even during symptom-free periods. Zileuton Extended-Release Tablets is 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 is 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. Manufactured by: Cohance Lifesciences Limited Telangana 500076, India Manufactured for: Rising Pharma Holdings, Inc. East Brunswick, NJ 08816 Made in India DRUGS/TS/23/2007 PIR20612-01 Revised: 05/2024 PATIENT INSTRUCTIONS LEAFLET (PIL)
17.2FDA-Approved Patient Labeling Zileuton Extended-Release Tablets Read the Patient Information that comes with Zileuton Extended-Release Tablets carefully before you start taking it 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 is Zileuton Extended-Release Tablets? Zileuton Extended-Release Tablets is 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 is 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… [Excerpted — this section continues on DailyMed.]
🔬 Clinical Studies ▾
14 CLINICAL STUDIES The efficacy of Zileuton Extended-Release Tablets was evaluated in a randomized, double-blind, parallel-group, placebo-controlled, multicenter trial of 12 weeks duration in patients 12 years of age and older with asthma. The 12-week trial included 199 patients randomized to Zileuton Extended-Release Tablets (two 600 mg tablets twice daily) and 198 to placebo. Eighty-three percent of patients were white, 48% were male, and the mean age was 34 years.
The mean baseline FEV 1 percent predicted was 58.5%. Assessment of efficacy was based upon forced expiratory volume in one second (FEV 1 ) at 12 weeks. Zileuton Extended-Release Tablets demonstrated a significantly greater improvement in mean change from baseline trough FEV 1 at 12 weeks compared to placebo (0.39 L vs.
0.27L; p=0.021). The mean change from baseline FEV 1 over the course of the 12-week study is shown in Figure 1. Secondary endpoints (PEFR and rescue beta-agonist use) were supportive of efficacy.
Examination of gender subgroups did not identify differences in response between men and women. The database was not large enough to assess whether there were differences in response in age or racial subgroups. Figure 1.
Mean Change from Baseline in Trough FEV 1 in 12-Week Clinical Trial in Patients with Asthma. Mean Change from Baseline in Trough Forced Expiratory Volume After 1 Second in 12-Week Clinical Trial in Patients With Asthma. *p ≤0.050. Endpoint analysis based on last-observation-carried-forward (LOCF) methodology figure
🧪 Nonclinical Toxicology ▾
13 NONCLINICAL TOXICOLOGY
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility In 2-year carcinogenicity studies, increases in the incidence of liver, kidney, and vascular tumors in female mice and a trend toward an increase in the incidence of liver tumors in male mice were observed at 450 mg/kg/day (providing approximately 5 times [females] or 8 times [males] the systemic exposure [AUC=64 μg hr/mL] achieved at the maximum recommended human daily oral dose). No increase in the incidence of tumors was observed at 150 mg/kg/day (providing approximately 2-3 times the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose).
In rats, an increase in the incidence of kidney tumors was observed in both sexes at 170 mg/kg/day (providing approximately 8 times [males] or 16 times [females] the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose). No increased incidence of kidney tumors was seen at 80 mg/kg/day (providing approximately 4 times [males] or 7 times [females] the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose). Although a dose-related increased incidence of benign Leydig cell tumors was observed, Leydig cell tumorigenesis was prevented by supplementing male rats with testosterone.
Zileuton was negative in genotoxicity studies including bacterial reverse mutation (Ames) using S. typhimurium and E. coli , chromosome aberration in human lymphocytes, in vitro unscheduled DNA synthesis (UDS), in rat hepatocytes with or without zileuton pretreatment and in mouse and rat kidney cells with zileuton pretreatment, and mouse micronucleus assays. However, a dose-related increase in DNA adduct formation was reported in kidneys and livers of female mice treated with zileuton. Although some evidence of DNA damage was observed in a UDS assay in hepatocytes isolated from Aroclor-1254-treated rats, no such finding was noticed in hepatocytes isolated from monkeys, where the metabolic profile of zileuton is more similar to that of humans.
In reproductive performance/fertility studies, zileuton produced no effects on fertility in rats at oral doses up to 300 mg/kg/day (providing approximately 12 times [male rats] and greater than 10 times [female rats] the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose). Comparative systemic exposure (AUC) is based on measurements in male rats or nonpregnant female rats at similar dosages. However, reduction in fetal implants was observed at oral doses of 150 mg/kg/day and higher (providing approximately 10 times the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose).
These effects were not seen at an estimated 4 times clinical exposure. Increases in gestation length, prolongation of estrus cycle, and increases in stillbirths were observed at oral doses of 70 mg/kg/day and higher (providing approximately 3 times the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose). In a perinatal/postnatal study in rats, reduced pup survival and growth were noted at an oral dose of 300 mg/kg/day (providing approximately greater than 10 times the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose).
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility In 2-year carcinogenicity studies, increases in the incidence of liver, kidney, and vascular tumors in female mice and a trend toward an increase in the incidence of liver tumors in male mice were observed at 450 mg/kg/day (providing approximately 5 times [females] or 8 times [males] the systemic exposure [AUC=64 μg hr/mL] achieved at the maximum recommended human daily oral dose). No increase in the incidence of tumors was observed at 150 mg/kg/day (providing approximately 2-3 times the systemic exposure [AUC] achieved at the maximum recommended human daily oral dose).
In rats, an increase in the incidence of kidney tumors was observed in both sexes at… [Excerpted — this section continues on DailyMed.]
📄 Package Label / Principal Display Panel ▾
———PRINCIPAL DISPLAY PANEL——— Rising ® NDC 64980- 206 -12 Zileuton Extended-Release Tablets 600 mg PHARMACIST: Dispense with patient information 2 Tablets BID 120 Tablets Rx only zileuton-container-label