Label: PARAFON DSC- chlorzoxazone tablet

  • Category: HUMAN PRESCRIPTION DRUG LABEL
  • DEA Schedule: None
  • Marketing Status: Abbreviated New Drug Application

Drug Label Information

Updated February 9, 2010

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  • DESCRIPTION

    Each caplet (round shaped tablet) contains:

    Chlorzoxazone                    500 mg

    Inactive ingredients: Colloidal Silicon Dioxide, Croscarmellose Sodium, docusate Sodium, lactose anhydrous, magnesium stearate, microcrystalline cellulose, sodium benzoate, D&C yellow No. 10 alum. Lake, FD&C blue no. 1 alum. Lake HT

    STRUCTURAL FORMULA
  • 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.

  • INDICATIONS AND USAGE

    Chlorzoxazone tablets are 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.

  • CONTRAINDICATIONS

    Chlorzoxazone tablets are contraindicated in patients with known intolerance to the drug.

  • 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.

  • 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.

  • 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 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.

  • 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.

  • DOSAGE AND ADMINISTRATION

    Usual Adult Dosage

    One caplet three or four times daily. If adequate response is not obtained with this dose, it may be increased to 1 ½ caplets (750 mg) three or four times daily. As improvement occurs dosage can usually be reduced.

  • HOW SUPPLIED

    Chlorzoxazone tablets 500 mg Tablets, (round shaped tablet, light green, imprinted "555/585" and "Barr" scored).

    NDC 68387-375-90, bottles of 90
    NDC 68387-375-30, bottles of 30

    Dispense in tight container as defined in the USP/NF.

    Store at controlled room temperature (15°–30°C, 59°–86°F).

    Manufactured for:
    Keltman Pharmaceuticals Inc.
    1 Lakeland Square, Suite A
    Flowood, Ms 39232

    R4

  • PRINCIPAL DISPLAY PANEL

    Package Label - Principal Display Panel – 90-count Bottle, 500 mg Tablets

    NDC 68387-375-90

    Rx Only

    chlorzoxazone Tablets

  • INGREDIENTS AND APPEARANCE
    PARAFON DSC 
    chlorzoxazone tablet
    Product Information
    Product TypeHUMAN PRESCRIPTION DRUGItem Code (Source)NDC:68387-375
    Route of AdministrationORAL
    Active Ingredient/Active Moiety
    Ingredient NameBasis of StrengthStrength
    Chlorzoxazone (UNII: H0DE420U8G) (Chlorzoxazone - UNII:H0DE420U8G) Chlorzoxazone500 mg
    Inactive Ingredients
    Ingredient NameStrength
    COLLOIDAL SILICON DIOXIDE (UNII: ETJ7Z6XBU4)  
    CROSCARMELLOSE SODIUM (UNII: M28OL1HH48)  
    DOCUSATE SODIUM (UNII: F05Q2T2JA0)  
    ANHYDROUS LACTOSE (UNII: 3SY5LH9PMK)  
    MAGNESIUM STEARATE (UNII: 70097M6I30)  
    CELLULOSE, MICROCRYSTALLINE (UNII: OP1R32D61U)  
    SODIUM BENZOATE (UNII: OJ245FE5EU)  
    D&C YELLOW NO. 10 (UNII: 35SW5USQ3G)  
    FD&C BLUE NO. 1 (UNII: H3R47K3TBD)  
    Product Characteristics
    ColorGREEN (light green) Score2 pieces
    ShapeROUNDSize17mm
    FlavorImprint Code 555;585;Barr
    Contains    
    Packaging
    #Item CodePackage DescriptionMarketing Start DateMarketing End Date
    1NDC:68387-375-9090 in 1 BOTTLE
    2NDC:68387-375-3030 in 1 BOTTLE
    Marketing Information
    Marketing CategoryApplication Number or Monograph CitationMarketing Start DateMarketing End Date
    ANDAANDA08989506/20/2004
    Labeler - Keltman Pharmaceuticals Inc. (362861077)
    Establishment
    NameAddressID/FEIBusiness Operations
    Barr Laboratories, Inc.824749340MANUFACTURE