Chlorzoxazone CHLORZOXAZONE ACTAVIS PHARMA, INC. FDA Approved 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, USP 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, USP contain the inactive ingredients docusate sodium, lactose monohydrate, magnesium stearate, microcrystalline cellullose, pregelatinized starch, sodium benzoate, and sodium starch glycolate. chemical structure
FunFoxMeds bottle
Substance Chlorzoxazone
Route
ORAL
Applications
ANDA089859

Drug Facts

Composition & Profile

Strengths
500 mg
Quantities
403 count 100 tablets
Treats Conditions
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
Pill Appearance
Shape: oval Color: white Imprint: WPI;39;68

Identifiers & Packaging

Container Type BOTTLE
UNII
H0DE420U8G
Packaging

HOW SUPPLIED Chlorzoxazone Tablets USP, 500 mg are available as oblong, scored, white tablets debossed with "WPI" on one side and "39|68" on the other side and are packaged in bottles of 100 (NDC 0591-2520-01) and 500 (NDC 0591-2520-05). Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature]. Dispense contents with a child-resistant closure (as required) and in a tight container as defined in the USP/NF. Keep this and all medications out of the reach of children. Manufactured In India By: Watson Pharma Private Limited Verna, Salcette Goa 403 722 INDIA Manufactured For: Teva Pharmaceuticals Parsippany, NJ 07054 Rev. B 8/2024; PRINCIPAL DISPLAY PANEL NDC 0591-2520-01 Chlorzoxazone Tablets, USP 500 mg Rx only 100 Tablets 1

Package Descriptions
  • HOW SUPPLIED Chlorzoxazone Tablets USP, 500 mg are available as oblong, scored, white tablets debossed with "WPI" on one side and "39|68" on the other side and are packaged in bottles of 100 (NDC 0591-2520-01) and 500 (NDC 0591-2520-05). Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature]. Dispense contents with a child-resistant closure (as required) and in a tight container as defined in the USP/NF. Keep this and all medications out of the reach of children. Manufactured In India By: Watson Pharma Private Limited Verna, Salcette Goa 403 722 INDIA Manufactured For: Teva Pharmaceuticals Parsippany, NJ 07054 Rev. B 8/2024
  • PRINCIPAL DISPLAY PANEL NDC 0591-2520-01 Chlorzoxazone Tablets, USP 500 mg Rx only 100 Tablets 1

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, USP 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, USP contain the inactive ingredients docusate sodium, lactose monohydrate, magnesium stearate, microcrystalline cellullose, pregelatinized starch, sodium benzoate, and sodium starch glycolate. chemical structure

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
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.
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 REACTIONS, contact Teva at 1-888-838-2872 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.


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