Home Drug Guide Metaxalone

Drug Guide

Generic Name

Metaxalone

Brand Names Skelaxin

Classification

Therapeutic: Muscle Relaxant

Pharmacological: Centrally Acting Skeletal Muscle Relaxant

FDA Approved Indications

  • Relief of discomfort associated with acute, painful musculoskeletal conditions

Mechanism of Action

Metaxalone acts centrally in the CNS to produce sedation and muscle relaxation; the precise mechanism is unknown but may involve sedative and analgesic effects that reduce muscle spasm and associated discomfort.

Dosage and Administration

Adult: Typically 800 mg three to four times daily as needed. Dose should be individualized based on response.

Pediatric: Not recommended for use in patients under 16 years due to lack of safety and efficacy data.

Geriatric: Caution advised; start at lower doses and monitor closely due to increased sensitivity and potential for adverse effects.

Renal Impairment: Use with caution; dosage adjustment may be necessary.

Hepatic Impairment: Use with caution; no specific dosage recommendations established.

Pharmacokinetics

Absorption: Well absorbed after oral administration

Distribution: Widely distributed in body tissues

Metabolism: Metabolized in the liver, specifics not well characterized

Excretion: Excreted primarily in urine as metabolites

Half Life: Approximately 1-2 hours

Contraindications

  • Hypersensitivity to metaxalone or any component of the formulation

Precautions

  • Use cautiously in patients with a history of hepatic impairment, hypersensitivity, or those taking other CNS depressants.
  • Pregnancy Category C; use only if clearly needed, weighing potential benefits and risks.

Adverse Reactions - Common

  • Drowsiness (Common)
  • Dizziness (Common)
  • Headache (Common)
  • GI upset (Common)

Adverse Reactions - Serious

  • Hepatotoxicity (Rare)
  • Allergic reactions including rash, urticaria (Rare)
  • Severe CNS depression (Rare)

Drug-Drug Interactions

  • CNS depressants (additive sedative effect)
  • Antidepressants (risk of serotonin syndrome)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor hepatic function if therapy is prolonged or if pre-existing liver disease.

Diagnoses:

  • Risk for injury related to sedation or dizziness

Implementation: Administer with food to decrease GI upset; monitor for adverse reactions; instruct patient on safety precautions.

Evaluation: Assess for effectiveness in reducing muscle spasm and pain; monitor for adverse effects such as excessive sedation or liver dysfunction.

Patient/Family Teaching

  • Do not operate heavy machinery or drive until response is known.
  • Avoid alcohol and other CNS depressants during therapy.
  • Report any signs of allergic reactions or unusual symptoms to healthcare provider.

Special Considerations

Black Box Warnings:

  • None currently

Genetic Factors: None identified as significant influencing pharmacokinetics or effects.

Lab Test Interference: None known.

Overdose Management

Signs/Symptoms: Drowsiness, dizziness, vomiting, lethargy,

Treatment: Supportive care; gastric lavage if ingestion was recent; activated charcoal may be administered; hemodialysis is generally not effective.

Storage and Handling

Storage: Store at room temperature, away from moisture and heat.

Stability: Stable under recommended storage conditions.

This guide is for educational purposes only and is not intended for clinical use.