Drug Facts
Composition & Profile
Identifiers & Packaging
HOW SUPPLIED Chlorzoxazone tablets USP are supplied as follows: 375 mg A white to off-white capsule shaped tablet, debossed "m338" on one side and plain on the other side, in bottles of 100 tablets, NDC 51862-338-01 500 mg A white to off-white capsule shaped tablet with functional scoring on one side and debossed "m339" on one side and plain on the other side, in bottles of 100 tablets, NDC 51862-339-01 750 mg A white to off-white capsule shaped tablet with two functional scores on both sides of the tablet. The top side is debossed with "3", "4", and "0" on left, middle, and right portions, respectively. The bottom side is debossed with "m" on each tablet portion. The tablet has a functional bisect score on each band of the tablet. The tablets are provided in bottles of 100 tablets. NDC 51862-340-01 Dispense in tight container as defined in the official compendium. Store at 20° to 25° C (68° to 77° F) [see USP Controlled Room Temperature].; PRINCIPAL DISPLAY PANEL - 375 mg Tablet Bottle Label NDC 51862-338-01 Chlorzoxazone Tablets, USP 375 mg Rx Only 100 Tablets mayne pharma PRINCIPAL DISPLAY PANEL - 375 mg Tablet Bottle Label; PRINCIPAL DISPLAY PANEL - 500 mg Tablet Bottle Label NDC 51862-339-01 Chlorzoxazone Tablets, USP 500 mg Rx Only 100 Tablets mayne pharma PRINCIPAL DISPLAY PANEL - 500 mg Tablet Bottle Label; PRINCIPAL DISPLAY PANEL - 750 mg Tablet Bottle Label NDC 51862-340-01 Chlorzoxazone Tablets, USP 750 mg Rx Only 100 Tablets mayne pharma PRINCIPAL DISPLAY PANEL - 750 mg Tablet Bottle Label
- HOW SUPPLIED Chlorzoxazone tablets USP are supplied as follows: 375 mg A white to off-white capsule shaped tablet, debossed "m338" on one side and plain on the other side, in bottles of 100 tablets, NDC 51862-338-01 500 mg A white to off-white capsule shaped tablet with functional scoring on one side and debossed "m339" on one side and plain on the other side, in bottles of 100 tablets, NDC 51862-339-01 750 mg A white to off-white capsule shaped tablet with two functional scores on both sides of the tablet. The top side is debossed with "3", "4", and "0" on left, middle, and right portions, respectively. The bottom side is debossed with "m" on each tablet portion. The tablet has a functional bisect score on each band of the tablet. The tablets are provided in bottles of 100 tablets. NDC 51862-340-01 Dispense in tight container as defined in the official compendium. Store at 20° to 25° C (68° to 77° F) [see USP Controlled Room Temperature].
- PRINCIPAL DISPLAY PANEL - 375 mg Tablet Bottle Label NDC 51862-338-01 Chlorzoxazone Tablets, USP 375 mg Rx Only 100 Tablets mayne pharma PRINCIPAL DISPLAY PANEL - 375 mg Tablet Bottle Label
- PRINCIPAL DISPLAY PANEL - 500 mg Tablet Bottle Label NDC 51862-339-01 Chlorzoxazone Tablets, USP 500 mg Rx Only 100 Tablets mayne pharma PRINCIPAL DISPLAY PANEL - 500 mg Tablet Bottle Label
- PRINCIPAL DISPLAY PANEL - 750 mg Tablet Bottle Label NDC 51862-340-01 Chlorzoxazone Tablets, USP 750 mg Rx Only 100 Tablets mayne pharma PRINCIPAL DISPLAY PANEL - 750 mg Tablet Bottle Label
Overview
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 CINO 2 Molecular Weight: 169.56 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. Inactive ingredients:, croscarmellose sodium, docusate sodium, lactose monohydrate, magnesium stearate, microcrystalline cellulose, pregelatinized corn starch and sodium benzoate. Chemical Structure
Indications & 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 & 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.
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 hepatoxicity 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 judgement 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, light- headedness, malaise, or overstimulation 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.
Storage & Handling
Dispense in tight container as defined in the official compendium. Store at 20° to 25° C (68° to 77° F) [see USP Controlled Room Temperature].
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