pharmacopeia
GET
/api/v1/drug/chlorzoxazone

Mechanism of action

Sourced from openFDA

Mechanism-of-action class: Unknown Cellular or Molecular Interaction.

Indications

Sourced from openFDA
  • 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.

Contraindications

Sourced from openFDA
  • Chlorzoxazone is contraindicated in patients with known intolerance to the drug.contraindicated

Dosage & administration

Sourced from openFDA

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

Sourced from openFDA

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.

Adverse reactions

Sourced from openFDA

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.

Overdosage

Sourced from openFDA

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.

Approval history

Sourced from openFDA
  • May 4, 1988ANDAANDA089853Aurobindo Pharma Ltd
  • May 4, 1988ANDAANDA089859Watson Labs
  • Jun 24, 2016ANDAANDA207483Anda Repository
  • Sep 12, 2019ANDAANDA212254Novitium Pharma
  • Jul 21, 2020ANDAANDA211849Dr Reddys Labs Sa
  • Nov 2, 2020ANDAANDA212743Ph Health
  • Jul 29, 2021ANDAANDA215158Senores Pharms
  • Apr 5, 2022ANDAANDA213126Rising

FAERS reports

View JSON
Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
1,278 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Nausea987.7%
  2. 2Dizziness957.4%
  3. 3Fatigue937.3%
  4. 4Pain927.2%
  5. 5Drug Ineffective826.4%
  6. 6Headache765.9%
  7. 7Anxiety665.2%
  8. 8Diarrhoea584.5%
  9. 9Chronic Kidney Disease564.4%
  10. 10Dyspnoea514.0%
  11. 11Somnolence514.0%
  12. 12Weight Decreased473.7%
  13. 13Back Pain463.6%
  14. 14Fall463.6%
  15. 15Completed Suicide433.4%

Literature

View JSON

Recent PubMed references pinned to Chlorzoxazone as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

View JSON

The 10 most recently updated of 10 ClinicalTrials.gov registrations naming Chlorzoxazone as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Frequently asked questions

How does Chlorzoxazone work?
Mechanism-of-action class: Unknown Cellular or Molecular Interaction.
What is Chlorzoxazone used for?
According to FDA labeling, Chlorzoxazone carries indications including: 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.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Chlorzoxazone?
Chlorzoxazone is classified as Oxazol, thiazine, and triazine derivatives, Muscle Relaxant, Unknown Cellular or Molecular Interaction, Centrally-mediated Muscle Relaxation, Decreased Central Nervous System Organized Electrical Activity, Striated Muscle Metabolic Alteration.
What are the brand names for Chlorzoxazone?
Chlorzoxazone is marketed under brand names including Lorzone.
What are the contraindications for Chlorzoxazone?
Chlorzoxazone labeling lists contraindications including: Chlorzoxazone is contraindicated in patients with known intolerance to the drug.. Always consult the full prescribing information and a clinician.
Note. Data for chlorzoxazone is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

Search pharmacopeia

Search drugs, classes, and ingredients