Chlorzoxazone is a prescription medicine (Muscle Relaxant). The sections below reproduce one FDA label for it, named under "Label". Products in other forms, strengths or from other makers have their own labels, which can differ.
- Type
- Prescription only (Rx)
- Drug class
- Muscle Relaxant
- Taken
- Oral
- Label
- Par Health USA, LLC, revised August 31, 2026 · full label on DailyMed
- Generic
- FDA-approved (11 companies) · details
What it is used for
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.
Who should not take it (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 tablets 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.
Side effects (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.
Is there a generic Chlorzoxazone?
Yes. The FDA has approved generic Chlorzoxazone from 11 companies whose approvals are active. The earliest of these was approved in 1988.
An FDA approval does not always mean the generic is already in pharmacies: patent disputes and settlements can delay a launch for years. Your pharmacist can tell you whether a generic is actually available and covered by your plan.
The FDA rates these generics as therapeutically equivalent to the brand ("A" rating): same active ingredient, strength, dosage form and effect. Pharmacists can usually substitute them unless the prescriber says otherwise.
Companies with an approved generic
Ajenat Pharms, Aurobindo Pharma Ltd, Dr Reddys Labs Sa, Macleods Pharms, Novitium Pharma, Ph Health, Pharmazone, Pharmobedient, Rising, Somerset Theraps Llc, Watson Labs
Brand-name versions
- Paraflex Ortho Mcneil Pharm Discontinued
- Parafon Forte Dsc Janssen R And D, approved 1958 Discontinued
Source: Drugs@FDA (via openFDA), checked October 29, 2026. Marketing status is what companies report to the FDA; whether a pharmacy stocks a product, and what your insurance covers, can differ.
Dosage:
we do not reproduce dosing instructions. The right dose depends on the person and the condition and is set by the prescriber or pharmacist. Dosage section of the full label.
Chlorzoxazone in the news
We have not covered this medicine yet. Latest news
Recalls
No recalls matched to this medicine in FDA enforcement reports from the last 3 years (or older ones still open). Search all recalls
Get alerts for Chlorzoxazone
We will email you if the FDA reports a recall, if its shortage status changes, or when we publish news about it — at most one email a day. No account needed.
Source: FDA structured product labeling, retrieved through openFDA. Label text is shown as published by the FDA, without editing; long sections are shortened, marked […]. openFDA data are not validated for clinical use — always check the current label and ask a doctor or pharmacist about your own treatment. Set ID 7c5a835d-3754-4c25-a0e2-335b8eceb2d2.