Drug Facts
Composition & Profile
Identifiers & Packaging
How Supplied/Storage and Handling Chlorzoxazone tablets, USP 500 mg are available as 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. Bottles of 30 Tablets NDC: 80425-0315-01 Bottles of 60 Tablets NDC: 80425-0315-02 Bottles of 90 Tablets NDC: 80425-0315-03 Store at controlled room temperature 15°- 30°C (59°-86° F). Dispense contents with a child-resistant closure (as required) and in a tight container as defined in the USP/NF. Keep out of the reach of children. Distributed by: Aurobindo Pharma USA, Inc. 279 Princeton-Hightstown Road East Windsor, NJ 08520 Manufactured by: Aurobindo Pharma Limited Hyderabad-500 032, India Distributed by: Advanced Rx Pharmacy of Tennessee, LLC Revised: 11/2021; label 1 label 2 label 3
- How Supplied/Storage and Handling Chlorzoxazone tablets, USP 500 mg are available as 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. Bottles of 30 Tablets NDC: 80425-0315-01 Bottles of 60 Tablets NDC: 80425-0315-02 Bottles of 90 Tablets NDC: 80425-0315-03 Store at controlled room temperature 15°- 30°C (59°-86° F). Dispense contents with a child-resistant closure (as required) and in a tight container as defined in the USP/NF. Keep out of the reach of children. Distributed by: Aurobindo Pharma USA, Inc. 279 Princeton-Hightstown Road East Windsor, NJ 08520 Manufactured by: Aurobindo Pharma Limited Hyderabad-500 032, India Distributed by: Advanced Rx Pharmacy of Tennessee, LLC Revised: 11/2021
- label 1 label 2 label 3
Overview
Chlorzoxazone USP is a centrally acting skeletal muscle relaxant, available as tablets of 500 mg for oral administration. Its chemical name is 5-Chloro-2-benzoxazolinone, and its structural formula is: Chlorzoxazone,USP is a white or practically white, practically odorless, crystalline powder. Chlorzoxazone is slightly soluble in water; sparingly soluble in alcohol, in isopropyl alcohol, and in methanol; soluble in solutions of alkali hydroxides and ammonia. Chlorzoxazone tablets contain the inactive ingredients -Lactose monohydrate USNF, Microcrystalline cellulose USNF, FD&C Yellow 6/Sunset Yellow FCF Aluminium lake, D&C Red 27/Phloxine Aluminium lake, Hypromellose USP (a) Binder solution Hypromellose USP (b), Polysarbate 80 USNF, Ethanol (96%v/v). Extragranrular Pregelatinized Starch USNF, Sodium starch glycolate USNF, Magnesium stearate USNF. FDA approved dissolution method differs from that of the USP. Description
Indications & Usage
Indications 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 & Administration
Usual Adult Dosage 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.
Warnings & Precautions
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. 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.
Contraindications
Chlorzoxazone is contraindicated in patients with known intolerance to the drug.
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.
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