SKELAXIN may enhance the effects of alcohol and other CNS depressants.
Drug Interactions The sedative effects of SKELAXIN and other CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants) may be additive.
Therefore, caution should be exercised with patients who take more than one of these CNS depressants simultaneously.
Deaths by deliberate or accidental overdose have occurred with metaxalone, particularly in combination with antidepressants, and have been reported with this class of drug in combination with alcohol.
When determining the LD 50 in rats and mice, progressive sedation, hypnosis, and finally respiratory failure were noted as the dosage increased.
In dogs, no LD 50 could be determined as the higher doses produced an emetic action in 15 to 30 minutes.
Treatment – Gastric lavage and supportive therapy.
Consultation with a regional poison control center is recommended.
SKELAXIN ® (metaxalone) is available as an 800 mg oval, scored pink tablet.
Chemically, metaxalone is 5-[(3,5- dimethylphenoxy) methyl]-2-oxazolidinone.
The empirical formula is C 12 H 15 NO 3 , which corresponds to a molecular weight of 221.25.
The structural formula is: Metaxalone is a white to almost white, odorless crystalline powder freely soluble in chloroform, soluble in methanol and in 96% ethanol, but practically insoluble in ether or water.
Each tablet contains 800 mg metaxalone and the following inactive ingredients: alginic acid, ammonium calcium alginate, B-Rose Liquid, corn starch, and magnesium stearate.
SKELAXIN (metaxalone) is available as an 800 mg oval, scored pink tablet inscribed with 8667 on the scored side and “S” on the other.
Available in bottles of 100 ( NDC 60793-136-01) and in bottles of 500 ( NDC 60793-136-05).
Store at Controlled Room Temperature, between 15°C and 30°C (59°F and 86°F).
Rx Only Prescribing Information as of April 2008.
Distributed by: King Pharmaceuticals, Inc., Bristol, TN 37620 Manufactured by: Corepharma LLC, Middlesex, NJ 08846
MECHANISM OF ACTION
Mechanism of Action The mechanism of action of metaxalone in humans has not been established, but may be due to general central nervous system depression.
Metaxalone has no direct action on the contractile mechanism of striated muscle, the motor end plate, or the nerve fiber.
INDICATIONS AND USAGE
SKELAXIN (metaxalone) is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomforts 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.
Metaxalone does not directly relax tense skeletal muscles in man.
Pediatric Use Safety and effectiveness in children 12 years of age and below have not been established.
Pregnancy Reproduction studies in rats have not revealed evidence of impaired fertility or harm to the fetus due to metaxalone.
Post marketing experience has not revealed evidence of fetal injury, but such experience cannot exclude the possibility of infrequent or subtle damage to the human fetus.
Safe use of metaxalone has not been established with regard to possible adverse effects upon fetal development.
Therefore, metaxalone tablets should not be used in women who are or may become pregnant and particularly during early pregnancy unless, in the judgement of the physician, the potential benefits outweigh the possible hazards.
Nursing Mothers It is not known whether this drug is secreted in human milk.
As a general rule, nursing should not be undertaken while a patient is on a drug since many drugs are excreted in human milk.
INFORMATION FOR PATIENTS
Information for Patients SKELAXIN may impair mental and/or physical abilities required for performance of hazardous tasks, such as operating machinery or driving a motor vehicle, especially when used with alcohol or other CNS depressants.
DOSAGE AND ADMINISTRATION
The recommended dose for adults and children over 12 years of age is one 800 mg tablet three to four times a day.