What is the recommended dosage and treatment duration for Metaxalone (metaxalone) for muscle spasms?

Metaxalone Dosage and Treatment Duration for Muscle Spasms

For muscle spasms, metaxalone should be administered at 800 mg three to four times daily, with a typical treatment duration of 7-14 days, and should be held on the day of any surgical procedure. 1

Dosing Recommendations

• Standard adult dosage: 800 mg orally 3-4 times daily
• Maximum daily dose: 3200 mg
• Typical treatment duration: 7-14 days (short-term use preferred)
• Administration: Can be taken with or without food, but consistent administration relative to meals is recommended

Treatment Algorithm

1. Initial assessment:

   • Confirm muscle spasm diagnosis
   • Rule out contraindications:
     • Significant hepatic or renal dysfunction
     • History of drug-induced or hemolytic anemia

2. Treatment initiation:

   • Start with 800 mg three times daily
   • If inadequate response after 3 days, may increase to 800 mg four times daily
   • Always use lowest effective dose to minimize adverse effects

3. Monitoring during treatment:

   • Assess effectiveness at 3-7 days
   • Monitor for central nervous system effects (drowsiness, dizziness, irritability)
   • Discontinue if no improvement after 7 days

4. Discontinuation:

   • No tapering required (unlike carisoprodol)
   • Hold medication on day of surgical procedures

Special Considerations

Contraindications

• Significant hepatic or renal dysfunction
• History of drug-induced or hemolytic anemia

Perioperative Management

• Hold metaxalone on the day of operation 1
• Unlike carisoprodol, metaxalone does not require tapering before discontinuation

Adverse Effects

• Common: drowsiness, dizziness, irritability
• Rare but serious: potential for serotonin syndrome when combined with serotonergic medications 2

Evidence Quality and Limitations

The evidence for metaxalone's efficacy is limited compared to other muscle relaxants. While it has fewer reported side effects than cyclobenzaprine or carisoprodol 3, there are no high-quality studies demonstrating superior efficacy over other muscle relaxants or placebo for long-term use.

The Mayo Clinic Proceedings consensus statement specifically recommends holding metaxalone on the day of operation, suggesting caution with perioperative use 1. Unlike some other muscle relaxants, metaxalone does not appear to cause significant withdrawal symptoms, making it potentially preferable to carisoprodol, which requires careful tapering to avoid withdrawal 1.

Combination Therapy

When metaxalone alone provides insufficient relief, consider:

• Adding non-pharmacological approaches (physical therapy, heat/cold therapy)
• Short-term combination with NSAIDs for inflammatory conditions
• Cognitive and behavioral interventions for chronic pain 1

Remember that muscle relaxants should generally be used for short-term management (≤2 weeks) as evidence for long-term efficacy is lacking, and the risk of adverse effects increases with prolonged use.