Zafirlukast 10 mg Tablet, Coated, 60-count
🆔 Identity & classification
Where does this data come from?
🏷️ RxNorm drug class
This medicine belongs to the Leukotriene Receptor Antagonist class.
Where does this data come from?
🏭 Manufacturer & labeler
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🩺 Clinical
Zafirlukast is used to prevent asthma symptoms. Zafirlukast is in a class of medications called leukotriene receptor antagonists (LTRAs). It works by blocking the action of certain natural substances that cause swelling and tightening of the airways.
Read the full MedlinePlus article ↗- No, it's quite different from a rescue inhaler. Zafirlukast is a daily tablet that works in the background to prevent asthma symptoms by blocking chemicals in your body called leuk...
- What exactly does zafirlukast do — is it the same as an inhaler?
- Timing really does matter here. Food can reduce how much zafirlukast your body actually absorbs by about 40%, which means it could be a lot less effective if you take it with a mea...
- Does it matter when I take it — can I just take it with breakfast?
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Supplement & herbal interactions
Some supplements/herbs that may interact with Zafirlukast — tap one for details:
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💊 What it looks like
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🧪 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.
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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.
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UNII M28OL1HH48
Croscarmellose sodium is a plant-based substance derived from cellulose. It acts as a disintegrant, helping tablets and capsules break down quickly in the digestive system so the medicine can be absorbed.
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UNII 3NXW29V3WO
Hypromellose is a plant-based thickener made from cellulose. It's used in medicines as a binder to hold ingredients together, a coating for tablets, and a thickener for liquids.
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UNII J2B2A4N98G
Lactose is a natural sugar derived from milk. In medications, it serves as a filler and binder to add bulk and help hold tablet or capsule ingredients together during manufacturing.
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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.
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UNII FZ989GH94E
Povidone is a synthetic polymer made from a plastic-like material. It acts as a binder to hold tablet ingredients together and as a disintegrant to help the tablet break apart in your stomach so the medicine can be absorbed.
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UNII 15FIX9V2JP
Titanium dioxide is a bright white mineral powder commonly used as a colorant and opacifying agent. It makes pills and tablets white or lighter in color and helps make coatings non-transparent.
7 inactive ingredients listed in the exact product block matched to this NDC.
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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
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💲 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 each | Per 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 | $0.9746 | $58.48 / 60 tablets |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Zafirlukast 10 mg 59651-0291-60 | Aurobindo | 60 tablets | $0.529 | — | Availability likely | — |
| Zafirlukast 10 mg 64380-0187-01 | Strides | 60 tablets | $0.529 | AB | Availability likely | — |
| Zafirlukast 10 mg 31722-0007-01 | Camber | 10 tablets | — | AB | FDA listed | — |
| Zafirlukast 10 mgthis 42291-0970-60 | AvKARE | 60 tablets | — | AB | FDA listed | — |
| Zafirlukast 10 mg 55111-0625-01 | Dr. | 100 tablets | — | AB | FDA listed | — |
Where does this data come from?
⏳ Availability & generic status
FDA-approved generic versions are listed, and recent pricing/market data suggests they may be available — see Therapeutic equivalents.
Where does this data come from?
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 42291-0970-60 You're viewing this | 60 TABLET, COATED in 1 BOTTLE (42291-970-60) | 2023-04-05 | Active |
🧭 About this NDC listing & data coverage
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. |
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📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
INDICATIONS AND USAGE Zafirlukast is indicated for the prophylaxis and chronic treatment of asthma in adults and children 5 years of age and older.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION Because food can reduce the bioavailability of zafirlukast, zafirlukast should be taken at least 1 hour before or 2 hours after meals. Adults and Children 12 years of age and older The recommended dose of zafirlukast in adults and children 12 years and older is 20 mg twice daily. Pediatric Patients 5 through 11 years of age The recommended dose of zafirlukast in children 5 through 11 years of age is 10 mg twice daily.
Elderly Patients Based on cross-study comparisons, the clearance of zafirlukast is reduced in elderly patients (65 years of age and older), such that C max and AUC are approximately twice those of younger adults. In clinical trials, a dose of 20 mg twice daily was not associated with an increase in the overall incidence of adverse events or withdrawals because of adverse events in elderly patients. Patients with Hepatic Impairment Zafirlukast is contraindicated in patients with hepatic impairment including hepatic cirrhosis (see CONTRAINDICATIONS ).
The clearance of zafirlukast is reduced in patients with stable alcoholic cirrhosis such that the C max and AUC are approximately 50 to 60% greater than those of normal adults. Zafirlukast has not been evaluated in patients with hepatitis or in long-term studies of patients with cirrhosis. Patients with Renal Impairment Dosage adjustment is not required for patients with renal impairment.
⛔ Contraindications ▾
CONTRAINDICATIONS Zafirlukast is contraindicated in patients who are hypersensitive to zafirlukast or any of its inactive ingredients. Zafirlukast is contraindicated in patients with hepatic impairment including hepatic cirrhosis.
⚠️ Warnings ▾
WARNINGS Hepatotoxicity: Cases of life-threatening hepatic failure have been reported in patients treated with zafirlukast. Cases of liver injury without other attributable cause have been reported from post-marketing adverse event surveillance of patients who have received the recommended dose of zafirlukast (40 mg/day). In most, but not all post-marketing reports, the patient's symptoms abated and the liver enzymes returned to normal or near normal after stopping zafirlukast.
In rare cases, patients have either presented with fulminant hepatitis or progressed to hepatic failure, liver transplantation and death. In extremely rare post-marketing cases, no clinical symptoms or signs suggestive of liver dysfunction were reported to precede the latter observations. Physicians may consider the value of liver function testing.
Periodic serum transaminase testing has not proven to prevent serious injury but it is generally believed that early detection of drug-induced hepatic injury along with immediate withdrawal of the suspect drug enhances the likelihood for recovery. Patients should be advised to be alert for signs and symptoms of liver dysfunction (e.g., right upper quadrant abdominal pain, nausea, fatigue, lethargy, pruritus, jaundice, flu-like symptoms, and anorexia) and to contact their physician immediately if they occur. Ongoing clinical assessment of patients should govern physician interventions, including diagnostic evaluations and treatment.
If liver dysfunction is suspected based upon clinical signs or symptoms (e.g., right upper quadrant abdominal pain, nausea, fatigue, lethargy, pruritus, jaundice, flu-like symptoms, anorexia, and enlarged liver), zafirlukast should be discontinued. Liver function tests, in particular serum ALT, should be measured immediately and the patient managed accordingly. If liver function tests are consistent with hepatic dysfunction, zafirlukast therapy should not be resumed.
Patients in whom zafirlukast was withdrawn because of hepatic dysfunction where no other attributable cause is identified should not be re-exposed to zafirlukast (see PRECAUTIONS, Information for Patients and ADVERSE REACTIONS ). Bronchospasm: Zafirlukast is not indicated for use in the reversal of bronchospasm in acute asthma attacks, including status asthmaticus. Therapy with zafirlukast can be continued during acute exacerbations of asthma.
Concomitant Warfarin Administration: Coadministration of zafirlukast with warfarin results in a clinically significant increase in prothrombin time (PT). Patients on oral warfarin anticoagulant therapy and zafirlukast should have their prothrombin times monitored closely and anticoagulant dose adjusted accordingly (see PRECAUTIONS, Drug Interactions ).
🤒 Adverse Reactions ▾
ADVERSE REACTIONS Adults and Children 12 years of age and older The safety database for zafirlukast consists of more than 4000 healthy volunteers and patients who received zafirlukast, of which 1723 were asthmatics enrolled in trials of 13 weeks duration or longer. A total of 671 patients received zafirlukast for 1 year or longer. The majority of the patients were 18 years of age or older; however, 222 patients between the age of 12 and 18 years received zafirlukast.
A comparison of adverse events reported by ≥1% of zafirlukast-treated patients, and at rates numerically greater than in placebo-treated patients, is shown for all trials in the table below. Adverse Event Zafirlukast N=4058 Placebo N=2032 Headache 12.9% 11.7% Infection 3.5% 3.4% Nausea 3.1% 2.0% Diarrhea 2.8% 2.1% Pain (generalized) 1.9% 1.7% Asthenia 1.8% 1.6% Abdominal Pain 1.8% 1.1% Accidental Injury 1.6% 1.5% Dizziness 1.6% 1.5% Myalgia 1.6% 1.5% Fever 1.6% 1.1% Back Pain 1.5% 1.2% Vomiting 1.5% 1.1% SGPT Elevation 1.5% 1.1% Dyspepsia 1.3% 1.2% The frequency of less common adverse events was comparable between zafirlukast and placebo.
Rarely, elevations of one or more liver enzymes have occurred in patients receiving zafirlukast in controlled clinical trials. In clinical trials, most of these have been observed at doses four times higher than the recommended dose. The following hepatic events (which have occurred predominantly in females) have been reported from postmarketing adverse event surveillance of patients who have received the recommended dose of zafirlukast (40 mg/day): cases of symptomatic hepatitis (with or without hyperbilirubinemia) without other attributable cause; and rarely, hyperbilirubinemia without other elevated liver function tests.
In most, but not all postmarketing reports, the patient's symptoms abated and the liver enzymes returned to normal or near normal after stopping zafirlukast. In rare cases, patients have presented with fulminant hepatitis or progressed to hepatic failure, liver transplantation and death (see WARNINGS , Hepatotoxicity and PRECAUTIONS, Information for Patients ) In clinical trials, an increased proportion of zafirlukast patients over the age of 55 years reported infections as compared to placebo-treated patients. A similar finding was not observed in other age groups studied.
These infections were mostly mild or moderate in intensity and predominantly affected the respiratory tract. Infections occurred equally in both sexes, were dose-proportional to total milligrams of zafirlukast exposure, and were associated with coadministration of inhaled corticosteroids. The clinical significance of this finding is unknown.
In rare cases, patients with asthma on zafirlukast may present with systemic eosinophilia, eosinophilic pneumonia, or clinical features of vasculitis consistent with Churg-Strauss syndrome, a condition which is often treated with systemic steroid therapy. Physicians should be alert to eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy presenting in their patients. These events have usually, but not always, been associated with reductions and/or withdrawal of steroid therapy.
The possibility that zafirlukast may be associated with emergence of Churg-Strauss syndrome can neither be excluded nor established (see PRECAUTIONS, Eosinophilic Conditions ). Neuropsychiatric adverse events, including insomnia and depression, have been reported in association with zafirlukast therapy (see PRECAUTIONS, Neuropsychiatric Events ). Hypersensitivity reactions, including urticaria, angioedema and rashes, with or without blistering, have also been reported in association with zafirlukast therapy.
Additionally, there have been reports of patients experiencing agranulocytosis, bleeding, bruising, or edema, arthralgia, myalgia, malaise, and pruritus in association with zafirlukast therapy. Rare cases of patients experiencing increased theophylline levels with or without cli…
🆘 Overdosage ▾
OVERDOSAGE No deaths occurred at oral zafirlukast doses of 2000 mg/kg in mice (approximately 210 times the maximum recommended daily oral dose in adults and children on a mg/m 2 basis), 2000 mg/kg in rats (approximately 420 times the maximum recommended daily oral dose in adults and children on a mg/m 2 basis), and 500 mg/kg in dogs (approximately 350 times the maximum recommended daily oral dose in adults and children on a mg/m 2 basis). Overdosage with zafirlukast has been reported in four patients surviving reported doses as high as 200 mg.
The predominant symptoms reported following zafirlukast overdose were rash and upset stomach. There were no acute toxic effects in humans that could be consistently ascribed to the administration of zafirlukast. It is reasonable to employ the usual supportive measures in the event of an overdose; e.g., remove unabsorbed material from the gastrointestinal tract, employ clinical monitoring, and institute supportive therapy, if required.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Mechanism of Action: Zafirlukast is a selective and competitive receptor antagonist of leukotriene D 4 and E 4 (LTD 4 and LTE 4 ), components of slow-reacting substance of anaphylaxis (SRSA). Cysteinyl leukotriene production and receptor occupation have been correlated with the pathophysiology of asthma, including airway edema, smooth muscle constriction, and altered cellular activity associated with the inflammatory process, which contribute to the signs and symptoms of asthma. Patients with asthma were found in one study to be 25 to 100 times more sensitive to the bronchoconstricting activity of inhaled LTD 4 than nonasthmatic subjects.
In vitro studies demonstrated that zafirlukast antagonized the contractile activity of three leukotrienes (LTC 4 , LTD 4 and LTE 4 ) in conducting airway smooth muscle from laboratory animals and humans. Zafirlukast prevented intradermal LTD 4 -induced increases in cutaneous vascular permeability and inhibited inhaled LTD 4 -induced influx of eosinophils into animal lungs. Inhalational challenge studies in sensitized sheep showed that zafirlukast suppressed the airway responses to antigen; this included both the early- and late-phase response and the nonspecific hyperresponsiveness.
In humans, zafirlukast inhibited bronchoconstriction caused by several kinds of inhalational challenges. Pretreatment with single oral doses of zafirlukast inhibited the bronchoconstriction caused by sulfur dioxide and cold air in patients with asthma. Pretreatment with single doses of zafirlukast attenuated the early- and late-phase reaction caused by inhalation of various antigens such as grass, cat dander, ragweed, and mixed antigens in patients with asthma.
Zafirlukast also attenuated the increase in bronchial hyperresponsiveness to inhaled histamine that followed inhaled allergen challenge. Clinical Pharmacokinetics and Bioavailability: Absorption Zafirlukast is rapidly absorbed following oral administration. Peak plasma concentrations are generally achieved 3 hours after oral administration.
The absolute bioavailability of zafirlukast is unknown. In two separate studies, one using a high fat and the other a high protein meal, administration of zafirlukast with food reduced the mean bioavailability by approximately 40%. Distribution Zafirlukast is more than 99% bound to plasma proteins, predominantly albumin.
The degree of binding was independent of concentration in the clinically relevant range. The apparent steady-state volume of distribution (Vss/F) is approximately 70 L, suggesting moderate distribution into tissues. Studies in rats using radiolabeled zafirlukast indicate minimal distribution across the blood-brain barrier.
Metabolism Zafirlukast is extensively metabolized. The most common metabolic products are hydroxylated metabolites which are excreted in the feces. The metabolites of zafirlukast identified in plasma are at least 90 times less potent as LTD 4 receptor antagonists than zafirlukast in a standard in vitro test of activity.
In vitro studies using human liver microsomes showed that the hydroxylated metabolites of zafirlukast excreted in the feces are formed through the cytochrome P450 2C9 (CYP2C9) pathway. Additional in vitro studies utilizing human liver microsomes show that zafirlukast inhibits the cytochrome P450 CYP3A4 and CYP2C9 isoenzymes at concentrations close to the clinically achieved total plasma concentrations (see Drug Interactions ). Excretion The apparent oral clearance (CL/f) of zafirlukast is approximately 20 L/h.
Studies in the rat and dog suggest that biliary excretion is the primary route of excretion. Following oral administration of radiolabeled zafirlukast to volunteers, urinary excretion accounts for approximately 10% of the dose and the remainder is excreted in feces. Zafirlukast is not detected in urine.
In the pivotal bioequivalence study, the mean terminal half-life of zafirlukast is approximately 10 hours in both normal adult subjects and p…
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Zafirlukast 10 mg Tablets, (NDC 42291-970-60) white, round, biconvex, film-coated tablets debossed with "P" on one side and "10" on the other, are supplied in opaque HDPE bottles of 60 tablets. Zafirlukast 20 mg Tablets, (NDC 42291-971-60) white, round, biconvex, film-coated tablets debossed with "P" on one side and "20" on the other, are supplied in opaque HDPE bottles of 60 tablets. Store at controlled room temperature, 20 to 25°C (68 to 77°F) [see USP].
Protect from light and moisture. Dispense in the original air-tight container.
📋 Description ▾
DESCRIPTION Zafirlukast is a synthetic, selective peptide leukotriene receptor antagonist (LTRA), with the chemical name 4-(5-cyclopentyloxy-carbonylamino-1-methyl-indol-3-ylmethyl)-3-methoxy-N-o-tolylsulfonylbenzamide. The molecular weight of zafirlukast is 575.7 and the structural formula is: The empirical formula is: C 31 H 33 N 3 O 6 S Zafirlukast, a fine white to pale yellow amorphous powder, is practically insoluble in water. It is slightly soluble in methanol and freely soluble in tetrahydrofuran, dimethylsulfoxide, and acetone.
Zafirlukast is supplied as 10 and 20 mg tablets for oral administration. Inactive Ingredients: Film-coated tablets containing croscarmellose sodium, lactose, magnesium stearate, microcrystalline cellulose, povidone, hypromellose, and titanium dioxide. Image
💬 Information for Patients ▾
PATIENT INFORMATION Zafirlukast Tablets Read the Patient Information leaflet before you start taking zafirlukast and each time you get a refill. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or your treatment.
What is Zafirlukast? Zafirlukast is a prescription medicine used to help prevent asthma attacks and for the long-term treatment of asthma symptoms in adults and children 5 years and older. It is not known if zafirlukast is safe and effective when used in children under 5 years old.
The effect of zafirlukast on growth in children has not been determined. Do not take zafirlukast if you need relief right away for a sudden asthma attack. If you get an asthma attack, you should follow the instructions your healthcare provider gave you for treating asthma attacks.
Who should not take Zafirlukast? Do not take zafirlukast if you: • are allergic to zafirlukast or any of the ingredients in zafirlukast. See the end of this leaflet for a complete list of ingredients in zafirlukast. • have problems with your liver.
What should I tell my healthcare provider before taking Zafirlukast? Before you take Zafirlukast, tell your healthcare provider if you: • have liver problems • have any other medical conditions • are pregnant or plan to become pregnant. It is not known if zafirlukast will harm your unborn baby.
Talk to your healthcare provider if you are pregnant or plan to become pregnant. • are breastfeeding or plan to breastfeed. Zafirlukast can pass into your milk; it is not known whether zafirlukast may harm your baby. Women who are breastfeeding should not take zafirlukast.
Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Zafirlukast may affect the way other medicines work, and other medicines may affect how zafirlukast works. Especially tell your healthcare provider if you take: • warfarin sodium (Coumadin, Jantoven) • erythromycin (ERYC, ERY-TAB, PCE) • theophylline (Elixophyllin, Theo-24, Theochron, Theolair, Uniphyl) • fluconazole (Diflucan) Know the medicines you take.
Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine. How should I take Zafirlukast? • Take zafirlukast exactly as your healthcare provider tells you to take it. • Take zafirlukast regularly, even if you do not have asthma symptoms. • Do not change your dose or stop taking zafirlukast without talking to your healthcare provider. • Do not stop taking or change the dose of your other asthma medicines unless your healthcare provider tells you to. • Take your prescribed dose of zafirlukast by mouth at least 1 hour before or 2 hours after meals. • Zafirlukast does not treat the symptoms of a sudden asthma attack. • Always have a short-acting beta2-agonist medicine (rescue inhaler) with you to treat sudden symptoms.
If you do not have a rescue inhaler medicine, talk to your healthcare provider to have one prescribed for you. • If you take too much zafirlukast, call your healthcare provider or go to the nearest hospital emergency room right away. What are the possible side effects of Zafirlukast? Zafirlukast may cause serious side effects, including: Severe liver problems.
In some cases, these liver problems can lead to liver failure, the need for a liver transplant or death. Tell your healthcare provider right away if you have: • pain or tenderness in the right upper side of your stomach area (abdomen) • nausea • tiredness • itchiness • yellowing of your skin or the whites of your eyes • flu-like symptoms • loss of appetite • dark (tea colored) urine • Inflammation of your blood vessels. Rarely, this can happen in people with asthma who take zafirlukast.
This usually, but not always, happens in people who also take a steroid medicine by mouth that is being stopped or the dose is being lowered. Tell your healthcare provider right away…