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chlorzoxazone (Parafon, Parafon-Forte)
Tradenames: Parafon, Forte.
Indications: muscle relaxant
Dosage: 250-500 mg PO TID/QID, max 750 mg QID
Tabs: 250 & 500 mg.
Pharmacokinetics:
1) effects last 3-4 hours
2) < 1% of drug is excreted unchanged in the urine
Adverse effects: (drug well tolerated by most patients)
1) nausea
2) dyspepsia
3) dizziness
4) drowsiness
5) discoloration of urine
6) hepatotoxicity: discontinue use
7) rash or itching: discontinue use
Laboratory:
- chlorzoxazone in serum/plasma
- chlorzoxazone in urine
Mechanism of action:
1) centrally-acting muscle relaxant
2) acts primarily at the spinal cord & subcortical areas of brain
3) inhibits multisynaptic reflex arcs involved in producing & maintaining skeletal muscle spasm
4) does not directly relax tense skeletal muscles
General
skeletal muscle relaxant (tranquilizer)
Properties
MISC-INFO: elimination route LIVER
KIDNEY
Database Correlations
PUBCHEM cid=2733
References
- The Pharmacological Basis of Therapeutics, 9th ed.
Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- Drug Information & Medication Formulary, Veterans Affairs,
Central California Health Care System, 1st ed., Ravnan et al
eds, 1998 - not on National VA formulary
Component-of
acetaminophen/chlorzoxazone