Chlorzoxazone 500 mg Tablet, 90-count — NDC 71335-2009-4 (Billing 71335-2009-04)
This is a package of 90 tablets of Chlorzoxazone 500 mg Tablet from Bryant Ranch Prepack, marketed since Aug 2020 and currently FDA-listed.
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): 004660
- GCN: 17901
- HICL (First Databank): 001941
- AHFS class code: 12:20.04.00
- RxCUI (RxNorm): 197502
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 Muscle Relaxant class.
Where does this data come from?
- RxClass (NLM) · catalog refreshed Oct 1, 2026
Clinical
Chlorzoxazone is used to relieve pain and stiffness caused by muscle strains and sprains. It is used in combination with physical therapy, analgesics (such as aspirin or acetaminophen), and rest.
Read the full MedlinePlus article ↗- It helps relieve discomfort from sudden, painful muscle and bone conditions. It is meant to be used along with rest, physical therapy and other measures, not by itself.
- You take it by mouth, usually three or four times a day. Your doctor may adjust the amount depending on how you respond, and it can often be lowered as you get better. Follow the d...
- Most people tolerate it well. Some feel drowsy, dizzy, lightheaded or a bit unwell, and a few feel over-stimulated. Your urine may change color, which isn't known to be a problem.
- Rarely, it can harm the liver. Stop the medicine and call if you have fever, rash, nausea, vomiting, unusual tiredness, upper right belly pain, dark urine or yellow skin or eyes. S...
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Chlorzoxazone — 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 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 | $0.2693 | $24.24 / 90 tablets |
Where does this data come from?
- CMS NADAC weekly file
- CMS ASP pricing files · refreshed Sep 20, 2026
- CMS Medicaid State Drug Utilization Data · refreshed Oct 3, 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 |
|---|---|---|---|---|
| 71335-2009-01 71335-2009-1 Main listing | 20 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-02 71335-2009-2 | 30 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-03 71335-2009-3 | 40 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-04 You're viewing this | 90 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-05 71335-2009-5 | 60 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-06 71335-2009-6 | 100 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-07 71335-2009-7 | 14 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-08 71335-2009-8 | 7 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
| 71335-2009-09 71335-2009-9 | 120 TABLET in 1 BOTTLE | 2022-02-10 | — | Active |
You're viewing one of 9 pack sizes for this product.
Pack size FAQ
What quantity is in this package?
How does this package differ from NDC 71335-2009-08?
What NDC number is used to bill for this package of Chlorzoxazone 500 mg Tablet?
Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Chlorzoxazone 500 mg 00591-2520-01 | Actavis | 100 tablets | $0.210 | AA | Availability likely | — |
| Chlorzoxazone 500 mg 16571-0726-01 | Rising | 100 tablets | $0.210 | AA | Availability likely | — |
| Chlorzoxazone 500 mg 59651-0306-01 | Aurobindo | 100 tablets | $0.210 | — | Availability likely | — |
| Chlorzoxazone 500 mg 70954-0085-10 | Novitium | 100 tablets | $0.210 | AA | Availability likely | — |
| Chlorzoxazone 500 mg 24470-0940-10 | Cintex | 100 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 50090-0315-00 | A-S | 30 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 50090-7504-00 | A-S | 30 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 51862-0339-01 | Mayne | 100 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 55289-0633-10 | PD-Rx | 10 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 63187-0317-20 | Proficient | 20 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 63629-1586-01 | Bryant | 20 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 70518-4364-00 | REMEDYREPACK | 90 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 71205-0711-30 | Proficient | 30 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 71335-1914-01 | Bryant | 20 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mgthis 71335-2009-04 | Bryant | 90 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 71335-2433-01 | Bryant | 20 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 71335-3122-00 | Bryant | 10 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 80425-0315-01 | Advanced | 30 tablets | — | AA | FDA listed | — |
| Chlorzoxazone 500 mg 80425-0507-01 | Advanced | 30 tablets | — | AA | FDA listed | — |
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 1, 2026
- FDA Orange Book · refreshed Oct 3, 2026
- CMS NADAC weekly file
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 Oct 3, 2026
What it looks like
Where does this data come from?
- FDA label on DailyMed · label index refreshed Oct 1, 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.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII 2LRS185U6K
D&C Red No. 27 is a synthetic red colorant used in medicines and cosmetics. It gives tablets, capsules, or liquids their red or reddish color so products are visually identifiable.
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UNII H77VEI93A8
A synthetic yellow dye used to color medications. It helps identify the drug and make it visually distinctive, with no effect on how the medicine works.
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UNII 0VUT3PMY82
Hypromellose 2910 is a plant-derived thickening agent made from cellulose. In medicines, it forms protective coatings on tablets or capsules, controls how fast the drug releases, and thickens liquid formulations.
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UNII EWQ57Q8I5X
Lactose monohydrate is a natural sugar derived from milk. It serves as a filler and binder in tablets and capsules, helping create the proper size, texture, and consistency of the medicine.
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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 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 6OZP39ZG8H
Polysorbate 80 is a synthetic emulsifier derived from sorbitol and oleic acid. It helps mix oil and water-based ingredients together in medications and improves how the product disperses in the body.
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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.
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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.
9 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
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.- 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 ▾
INDICATIONS AND USAGE Chlorzoxazone is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of this drug has not been clearly identified, but may be related to its sedative properties. Chlorzoxazone does not directly relax tense skeletal muscles in man.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION Usual Adult Dosage Chlorzoxazone tablets USP, 375 mg: One tablet three or four times daily. If adequate response is not obtained with this dose, the 375 mg tablets may be increased to two tablets (750 mg) three or four times daily. As improvement occurs dosage can usually be reduced.
Chlorzoxazone tablets USP, 500 mg: One tablet three or four times daily. If adequate response is not obtained with this dose, it may be increased to one and one-half tablets (750 mg) three or four times daily. As improvement occurs dosage can usually be reduced.
Chlorzoxazone tablets USP, 750 mg: 1/3 tablet (250 mg) three or four times daily. Initial dosage for painful musculoskeletal conditions should be 2/3 tablet (500 mg) three or four times daily. If adequate response is not obtained with this dose, it may be increased to one tablet (750 mg) three or four times daily.
As improvement occurs dosage can usually be reduced.
⛔ Contraindications ▾
CONTRAINDICATIONS Chlorzoxazone is contraindicated in patients with known intolerance to the drug.
⚠️ Warnings ▾
WARNINGS Serious (including fatal) hepatocellular toxicity has been reported rarely in patients receiving chlorzoxazone. The mechanism is unknown but appears to be idiosyncratic and unpredictable. Factors predisposing patients to this rare event are not known.
Patients should be instructed to report early signs and/or symptoms of hepatotoxicity such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, or jaundice. Chlorzoxazone should be discontinued immediately and a physician consulted if any of these signs or symptoms develop. Chlorzoxazone use should also be discontinued if a patient develops abnormal liver enzymes (e.g., AST, ALT, alkaline phosphatase and bilirubin.) The concomitant use of alcohol or other central nervous system depressants may have an additive effect.
Usage in Pregnancy: The safe use of chlorzoxazone has not been established with respect to the possible adverse effects upon fetal development. Therefore, it should be used in women of childbearing potential only when, in the judgment of the physician, the potential benefits outweigh the possible risks.
🤒 Adverse Reactions ▾
ADVERSE REACTIONS Chlorzoxazone containing products are usually well tolerated. It is possible in rare instances that chlorzoxazone may have been associated with gastrointestinal bleeding. Drowsiness, dizziness, lightheadedness, malaise, or over-stimulation may be noted by an occasional patient.
Rarely, allergic type skin rashes, petechiae, or ecchymoses may develop during treatment. Angioneurotic edema or anaphylactic reactions are extremely rare. There is no evidence that the drug will cause renal damage.
Rarely, a patient may note discoloration of the urine resulting from a phenolic metabolite of chlorzoxazone. This finding is of no known clinical significance. To report SUSPECTED ADVERSE EVENTS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800- FDA-1088 or http://www.fda.gov/ for voluntary reporting of adverse reactions.
🆘 Overdosage ▾
OVERDOSAGE Symptoms: Initially, gastrointestinal disturbances such as nausea, vomiting, or diarrhea together with drowsiness, dizziness, lightheadedness or headache may occur. Early in the course there may be malaise or sluggishness followed by marked loss of muscle tone, making voluntary movement impossible. The deep tendon reflexes may be decreased or absent.
The sensorium remains intact, and there is no peripheral loss of sensation. Respiratory depression may occur with rapid, irregular respiration and intercostal and substernal retraction. The blood pressure is lowered, but shock has not been observed.
Treatment: Gastric lavage or induction of emesis should be carried out, followed by administration of activated charcoal. Thereafter, treatment is entirely supportive. If respirations are depressed, oxygen and artificial respiration should be employed and a patent airway assured by use of an oropharyngeal airway or endotracheal tube.
Hypotension may be counteracted by use of dextran, plasma, concentrated albumin or a vasopressor agent such as norepinephrine. Cholinergic drugs or analeptic drugs are of no value and should not be used.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Chlorzoxazone is a centrally-acting agent for painful musculoskeletal conditions. Data available from animal experiments as well as human study indicate that chlorzoxazone acts primarily at the level of the spinal cord and subcortical areas of the brain where it inhibits multisynaptic reflex arcs involved in producing and maintaining skeletal muscle spasm of varied etiology. The clinical result is a reduction of the skeletal muscle spasm with relief of pain and increased mobility of the involved muscles.
Blood levels of chlorzoxazone can be detected in people during the first 30 minutes and peak levels may be reached, in the majority of the subjects, in about 1 to 2 hours after oral administration of chlorzoxazone. Chlorzoxazone is rapidly metabolized and is excreted in the urine, primarily in a conjugated form as the glucuronide. Less than one percent of a dose of chlorzoxazone is excreted unchanged in the urine in 24 hours.
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Chlorzoxazone tablets USP are supplied as follows: 500 mg A light orange to orange round shaped, flat hexagonal, beveled debossed with “N” on one side of break line and “500” on other side of break line and plain on other side. NDC: 71335-2009-1: 20 TABLETs in a BOTTLE NDC: 71335-2009-2: 30 TABLETs in a BOTTLE NDC: 71335-2009-3: 40 TABLETs in a BOTTLE NDC: 71335-2009-4: 90 TABLETs in a BOTTLE NDC: 71335-2009-5: 60 TABLETs in a BOTTLE NDC: 71335-2009-6: 100 TABLETs in a BOTTLE NDC: 71335-2009-7: 14 TABLETs in a BOTTLE NDC: 71335-2009-8: 7 TABLETs in a BOTTLE NDC: 71335-2009-9: 120 TABLETs in a BOTTLE Repackaged/Relabeled by: Bryant Ranch Prepack, Inc.
Burbank, CA 91504
📋 Description ▾
DESCRIPTION Each 375 mg chlorzoxazone tablet contains: Chlorzoxazone USP 375 mg. Each 500 mg chlorzoxazone tablet contains: Chlorzoxazone USP 500 mg. Each 750 mg chlorzoxazone tablet contains: Chlorzoxazone USP 750 mg.
Chemical Name: 5-Chloro-2-benzoxazolinone. Structural Formula: Molecular Formula: C 7 H 4 ClNO 2 Molecular Weight: 169.56 Chlorzoxazone, USP is a white or practically white, practically odorless, crystalline powder. Chlorzoxazone USP is slightly soluble in water; sparingly soluble in alcohol, in isopropyl alcohol, and in methanol; soluble in solutions of alkali hydroxides and ammonia.
Inactive ingredients: 375 mg contains colloidal silicon dioxide, corn starch, croscarmellose sodium, docusate sodium with sodium benzoate, lactose monohydrate, magnesium stearate and microcrystalline cellulose. 500 mg contains D&C Red 27/Phloxine Aluminium lake, FD&C Yellow 6/Sunset Yellow FCF Aluminium lake, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, polysorbate 80, pregelatinized starch, sodium starch glycolate. 750 mg contains colloidal silicon dioxide, corn starch, croscarmellose sodium, docusate sodium with sodium benzoate, lactose monohydrate, magnesium stearate and microcrystalline cellulose.
Meets USP dissolution test 5 for 500 mg. FDA approved dissolution method differs from that of the USP for 375 mg and 750 mg.
⚠️ Precautions ▾
PRECAUTIONS Chlorzoxazone should be used with caution in patients with known allergies or with a history of allergic reactions to drugs. If a sensitivity reaction occurs such as urticaria, redness, or itching of the skin, the drug should be stopped. If any symptoms suggestive of liver dysfunction are observed, the drug should be discontinued.
📄 Package Label / Principal Display Panel ▾
Chlorzoxazone 500mg Tablet Label
Medicare Part D spend CMS · PART D · 2026 (Q1)
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. |