Metaxalone

Metaxalone is a prescription medication used for the treatment of musculoskeletal pain.

• Metaxalone is available under the following different brand names: Skelaxin

Adult and pediatric dosage

Tablet

• 400mg
• 800mg

Musculoskeletal Pain

Adult dosage

• 800 mg orally every 6-8 hours

Pediatric dosage

• Children below 12 years: Safety and efficacy not established
• Children above 12 years: 800 mg orally every 6-8 hours

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

Common side effects of Metaxalone include:

• drowsiness,
• dizziness,
• headache,
• nervousness,
• irritability,
• nausea,
• vomiting,
• upset stomach, or
• skin rash.

Serious side effects of Metaxalone include:

• stomach pain,
• loss of appetite,
• low fever,
• dark urine,
• clay-colored stools, and
• yellowing skin and eyes (jaundice).

Rare side effects of Metaxalone include:

• none 

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Metaxalone has severe interactions with no other drugs.
• Metaxalone has serious interactions with the following drugs:
  • abametapir
  • apalutamide
  • benzhydrocodone/acetaminophen
  • calcium/magnesium/potassium/sodium oxybates
  • fexinidazole
  • hydrocodone
  • idelalisib
  • ivosidenib
  • lopinavir
  • metoclopramide intranasal
  • sodium oxybate
  • sufentanil SL
  • tucatinib
  • voxelotor
• Metaxalone has moderate interactions with at least 174 other drugs.
• Metaxalone has minor interactions with the following drugs:
  • eucalyptus
  • levoketoconazole
  • ribociclib
  • sage

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

Contraindications

• Hypersensitivity
• History of drug-induced hemolytic anemia
• Significant renal/hepatic impairment

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Metaxalone?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Metaxalone?”

Cautions

• CNS depression may occur
• Sedative effects may be potentiated when used with other sedatives
• Medication is poorly tolerated by the elderly
• Bioavailability may increase in female patients
• Use caution in renal and hepatic impairment
• Safety and efficacy not established in children below 12 years
• May impair physical or mental abilities; caution patient against operating heavy machinery or performing tasks requiring mental alertness
• Serotonin syndrome
  • Cases of serotonin syndrome, a potentially life-threatening condition, reported during concomitant use of serotonergic drugs with this drug when used within recommended dosage range and with metaxalone as a single agent taken at doses higher than the recommended dose (see drug interaction overview)
  • Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, coma), autonomic instability (e.g., tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination, rigidity), and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea); the onset of symptoms generally occurs within several hours to a few days but may occur later than that
  • Discontinue therapy if serotonin syndrome suspected
• Drug interaction overview
  • Sedative effects of this drug and other CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants) may be additive; caution should be exercised with patients who take more than one of these CNS depressants simultaneously
  • Serotonin syndrome has occurred with concomitant use of serotonergic drugs, including selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, opioids (particularly fentanyl, meperidine, and methadone), drugs that affect the serotonergic neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), and drugs that impair metabolism of serotonin (including monoamine oxidase (MAO) inhibitors, both those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue)

Pregnancy and Lactation

• Use with caution if the benefits outweigh the risks during pregnancy
• Lactation
  • Unknown if excreted in breast milk; not recommended