From the Guidelines
Metaxalone is a centrally acting skeletal muscle relaxant.
Key Characteristics
- It does not act directly on skeletal muscle, and its precise mechanism of action is unclear 1.
- It has multiple central nervous system adverse effects, including drowsiness, dizziness, and irritability 1.
- Contraindications include significant hepatic or renal dysfunction, and it has been associated with drug-induced, hemolytic, or other anemias 1.
Clinical Use
- It is used to reduce muscle spasm and is recommended for the treatment of skeletal pain, myalgias, and arthralgias 1.
- In the context of preoperative management, it is recommended to hold metaxalone on the day of operation 1.
- It is considered a less-sedating muscle relaxant option, along with methocarbamol, for the management of musculoskeletal or inflammatory pain 1.
From the FDA Drug Label
Metaxalone tablets are 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 a medication used as an adjunct to rest, physical therapy, and other measures for the relief of discomforts associated with acute, painful musculoskeletal conditions. Its exact mechanism of action is unknown, but it may be related to its sedative properties. It does not directly relax tense skeletal muscles in humans. 2
From the Research
Definition and Uses of Metaxalone
- Metaxalone is a centrally acting muscle relaxant used to treat muscle spasms and discomfort 3
- It is one of the commonly prescribed skeletal muscle relaxants, along with cyclobenzaprine and carisoprodol 3
Mechanism of Action and Side Effects
- The mechanism of action of metaxalone is unknown, but it is believed to have serotonergic effects at supratherapeutic concentrations 4
- Metaxalone has been associated with serotonin syndrome, a potentially life-threatening condition, especially when taken in overdose or with other pro-serotonergic medications 4, 5
- Common side effects of metaxalone include lethargy, anticholinergic effects, and toxicity in overdose or combination with other substances 3
Pharmacological Properties and Interactions
- Metaxalone is a biopharmaceutical classification systems (BCS) class II drug with poor aqueous solubility and high permeability 6
- It can interact with other medications, such as selective serotonin reuptake inhibitors, and increase the risk of serotonin syndrome 4, 5
- Metaxalone can also interact with other central nervous system depressants, such as ethanol and chlorpheniramine, and increase the risk of adverse effects 7
Toxicity and Overdose
- Metaxalone overdose can be toxic and potentially fatal, especially when combined with other substances 7
- Symptoms of metaxalone overdose include altered mental status, seizure-like activity, hyperthermia, rigidity, and myoclonus 4, 5
- Treatment of metaxalone overdose typically involves supportive care, such as intubation, sedation, and active cooling, as well as management of any resulting complications, such as serotonin syndrome 4, 5