Class: Skeletal muscle relaxant
- Tablets 800 mg
Mechanism of action not established, but may be caused by general CNS depression. No direct action on the contractile mechanism of striated muscle, the motor endplate, or the nerve fiber. Does not directly relax tense skeletal muscles.
Under fasting conditions, C max is 1653 ng/mL, T max is approximately 3 h and mean t ½ is 8 h. Under fed conditions, C max increased by 194%, T max is approximately 4.9 h and mean t ½ is 4.2 h (single 800 mg dose).
Indications and Usage
As an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful, musculoskeletal conditions.
Standard considerations; known tendency to drug-induced hemolytic or other anemias; significantly impaired renal or hepatic function.
Dosage and AdministrationAdults and children older than 12 yr of age
PO 800 mg 3 to 4 times daily.
Store tablets at controlled room temperature (59° to 86°F).
Drug InteractionsAlcohol, barbiturates, CNS depressants
Effects may be enhanced by metaxalone.
Laboratory Test Interactions
False-positive Benedict tests, caused by an unknown reducing substance, have been noted. A glucose-specific test will differentiate findings.
Drowsiness; dizziness; headache; nervousness; irritability.
Nausea; vomiting; GI upset.
Hypersensitivity reaction (light rash with or without pruritus); leukopenia; hemolytic anemia; jaundice; anaphylactoid reactions (rare).
Do not use during pregnancy, especially during early pregnancy, or in women who may become pregnant, unless the potential benefits outweigh the potential hazards to the fetus.
Safety and efficacy not determined in children younger than 12 yr of age.
Administer with great care to patients with preexisting liver damage and perform serial liver function studies as required.
- Advise patient or caregiver to read the patient information leaflet before starting therapy and with each refill.
- Advise patient that medication is usually started at a low dose and then gradually increased until max benefit is obtained.
- Caution patient to take as prescribed and not to stop taking or change the dose unless advised by health care provider.
- Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
- Advise patient that if a dose is missed to skip that dose and take the next dose at the regularly scheduled time. Caution patient to never take 2 doses at the same time.
- Instruct patient to avoid alcoholic beverages and other depressants while taking this medication.
- Emphasize importance of other adjunctive measures (eg, rest, physical therapy) as part of the management of musculoskeletal conditions.
- Instruct patient to contact health care provider if symptoms do not appear to be getting better, are getting worse, or if skin rash, yellowish discoloration of the skin or eyes, or bothersome adverse reactions (eg, drowsiness, dizziness, nausea) occur.
- Advise patient that drug may cause drowsiness or dizziness and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
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