Skelaxin Patient Education Monograph

CATEGORIES: Pain, musculoskeletal; FDA Approved 1962 Aug; Pregnancy Category C

Drug Classes: Musculoskeletal agents; Relaxants, skeletal muscle


$29.94 (Musculoskeletal Pain; Skelaxin; 400 mg; 6 tablets/day; 10 day supply)

Each pale rose, scored tablet contains: metaxalone, 400 mg.
Metaxalone has the following chemical name: 5-[(3, 4-dimethylphenoxy)methyl]-2-oxazolidinone.

The mechanism of action of metaxalone in humans has not been established yet , but may be due to general central nervous system depression. It has direct action on the contractile mechanism of striated muscle, the motor end plate or the nerve fiber.

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.

Metaxalone is contraindicated for individuals who have previously shown hypersensitivity to the drug. Metaxalone should not be administered to patients with a known tendency to drug induced, hemolytic, or other anemias. It is also contraindicated in patients with significantly impaired renal or hepatic function.

There have been noted some elevation in cephalin flocculation tests without concurrent changes in other liver function parameters. Hence, it is recommended that metaxalone be administered with great care to patients with pre-existing liver damage and that serial liver function studies be performed as required.
False-positive Benedict’s tests, due to an unknown reducing substance, have been noted. A glucose-specific test will differentiate findings.

Reproduction studies have been performed in rats and have revealed no evidence of impaired fertility or any harm to the fetus due to metaxalone. Reactions reports from marketing experience have not revealed evidence of fetal injury, but such experience cannot totally exclude the possibility of infrequent or subtle damage to the human fetus. Up to this moment, 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 judgment 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.

Pediatric Use
Safety and effectiveness in children 12 years of age and below have not been established yet.

The most frequent reactions to metaxalone include nausea, vomiting, gastrointestinal upset, drowsiness, dizziness, headache, and nervousness or “irritability.” Other adverse reactions are: hypersensitivity reactions, characterized by a light rash with or without pruritus; leukopenia; hemolytic anemia; jaundice.

Gastric lavage and supportive therapy as indicated. (When determining the LD50 in rats and mice, progressive sedation, hypnosis and finally respiratory failure were noted as the dosage increased. In dogs, no LD50 could be determined as the higher doses produced an emetic action in 15-30 minutes). No documented case of major toxicity has been reported.

The recommended dose for adults and children over 12 years of age is 2 tablets (800 mg) 3 to 4 times a day.

Skelaxin is available as a 400 mg pale rose tablet, inscribed with “8862″ on the scored side and “C” on the other.
Storage: Store at controlled room temperature, between 15-30°C (59-86°F).