Dosing & Uses
Dosage Forms & Strengths
tablet
- 375mg
- 500mg
- 750mg
Musculoskeletal Pain
Indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions
250-750 mg PO q6-8hr
Dosage Forms & Strengths
tablet
- 375mg
- 500mg
- 750mg
Muscle Spasms
20 mg/kg/day PO divided q6-8hr or 600 mg/m²/day PO divided q6-8hr
Musculoskeletal conditions
250 mg PO q6-12hr; increase PRN to 750 mg PO q6-8hr
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
1-10%
Lightheadedness
Dizziness
Drowsiness
Excitement, Paradoxical
Somnolence
Malaise
Rash
Angioneurotic edema
<1%
Gastrointestinal hemorrhage (rare)
Hepatotoxicity (rare)
Anaphylaxis (rare)
Warnings
Contraindications
Hypersensitivity to drug or excipients
Cautions
May cause CNS depression and impair physical and mental alertness; avoid performing tasks that require mental alertness
May take with food to avoid stomach upset
Poor tolerance by the elderly
Hepatotoxicity
- Serious (including fatal) hepatocellular toxicity has been reported rarely in patients receiving therapy; 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; therapy should be discontinued immediately, and a physician consulted if signs or symptoms develop
- Therapy should also be discontinued if a patient develops abnormal liver enzymes (eg, AST, ALT, alkaline phosphatase and bilirubin)
- The concomitant use of alcohol or other central nervous system depressants may have an additive effect
Pregnancy & Lactation
Pregnancy Category: C
Lactation: not known if excreted in breast milk
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Blocks interneuronal conduction in spinal cord and subcortical brain areas by depressing polysynaptic reflexes
Pharmacokinetics
Half-life: 66 min
Onset: 1 hr
Duration: 6-12 hr
Peak Plasma Time: 1-4 hr
Peak Plasm Concentration: 9-20 mcg/mL
Metabolism: Rapid hepatic glucuronidation
Metabolites: 6-hydroxychlorzoxazone (inactive; rapidly excreted in urine)
Excretion: Urine (primarily)
Images
Patient Handout
Formulary
Adding plans allows you to compare formulary status to other drugs in the same class.
To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.
Adding plans allows you to:
- View the formulary and any restrictions for each plan.
- Manage and view all your plans together – even plans in different states.
- Compare formulary status to other drugs in the same class.
- Access your plan list on any device – mobile or desktop.
