Label: CHLORZOXAZONE tablet
- NDC Code(s): 59651-306-01, 59651-306-05
- Packager: Aurobindo Pharma Limited
- Category: HUMAN PRESCRIPTION DRUG LABEL
- DEA Schedule: None
- Marketing Status: Abbreviated New Drug Application
Updated January 29, 2022
If you are a consumer or patient please visit this version.
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)
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.
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.
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.
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.
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.
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.
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.
- DOSAGE AND ADMINISTRATION
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 100 with child-resistant closure NDC 59651-306-01
Bottles of 500 NDC 59651-306-05
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.
Aurobindo Pharma USA, Inc.
279 Princeton-Hightstown Road
East Windsor, NJ 08520
Aurobindo Pharma Limited
Hyderabad-500 032, India
- PACKAGE LABEL-PRINCIPAL DISPLAY PANEL - 500 mg (100 Tablets Bottle)
INGREDIENTS AND APPEARANCE
Product Information Product Type HUMAN PRESCRIPTION DRUG Item Code (Source) NDC:59651-306 Route of Administration ORAL Active Ingredient/Active Moiety Ingredient Name Basis of Strength Strength CHLORZOXAZONE (UNII: H0DE420U8G) (CHLORZOXAZONE - UNII:H0DE420U8G) CHLORZOXAZONE 500 mg Inactive Ingredients Ingredient Name Strength LACTOSE MONOHYDRATE (UNII: EWQ57Q8I5X) MICROCRYSTALLINE CELLULOSE (UNII: OP1R32D61U) FD&C YELLOW NO. 6 (UNII: H77VEI93A8) D&C RED NO. 27 (UNII: 2LRS185U6K) HYPROMELLOSE 2910 (3 MPA.S) (UNII: 0VUT3PMY82) POLYSORBATE 80 (UNII: 6OZP39ZG8H) ALCOHOL (UNII: 3K9958V90M) STARCH, CORN (UNII: O8232NY3SJ) SODIUM STARCH GLYCOLATE TYPE A POTATO (UNII: 5856J3G2A2) MAGNESIUM STEARATE (UNII: 70097M6I30) Product Characteristics Color ORANGE (Light orange to orange) Score 2 pieces Shape ROUND (flat, hexagonal) Size 13mm Flavor Imprint Code N;500 Contains Packaging # Item Code Package Description Marketing Start Date Marketing End Date 1 NDC:59651-306-01 100 in 1 BOTTLE; Type 0: Not a Combination Product 08/03/2020 2 NDC:59651-306-05 500 in 1 BOTTLE; Type 0: Not a Combination Product 08/03/2020 Marketing Information Marketing Category Application Number or Monograph Citation Marketing Start Date Marketing End Date ANDA ANDA089853 08/03/2020 Labeler - Aurobindo Pharma Limited (650082092) Establishment Name Address ID/FEI Business Operations APL HEALTHCARE LIMITED 650844777 ANALYSIS(59651-306) , MANUFACTURE(59651-306)