Skelaxin


metaxalone

(me-tax -a-lone) metaxalone,

Skelaxin

(trade name)

Classification

Therapeutic: skeletal muscle relaxants
Pregnancy Category: UK

Indications

Muscle spasm associated with acute painful musculoskeletal conditions (with rest and physical therapy).

Action

Skeletal muscle relaxation, probably as a result of CNS depression.

Therapeutic effects

Skeletal muscle relaxation.

Pharmacokinetics

Absorption: Well absorbed following oral administration.Distribution: Unknown.Metabolism and Excretion: Mostly metabolized by the liver; metabolites excreted in urine.Half-life: 2–3 hr.

Time/action profile

ROUTEONSETPEAKDURATION
PO1 hr2 hr4–6 hr

Contraindications/Precautions

Contraindicated in: Hypersensitivity;Significant hepatic/renal impairment;History of drug-induced hemolytic anemia or other anemia.Use Cautiously in: Hepatic impairment;History of seizures; Obstetric / Lactation / Pediatric: Pregnancy, lactation or children ≤12 yr (safety not established); Geriatric: Appears on Beers list. Poorly tolerated due to anticholinergic effects.

Adverse Reactions/Side Effects

Central nervous system

  • drowsiness (most frequent)
  • dizziness (most frequent)
  • confusion
  • headache
  • irritability
  • nervousness

Gastrointestinal

  • nausea (most frequent)
  • anorexia
  • dry mouth
  • GI upset
  • vomiting

Genitourinary

  • urinary retention

Interactions

Drug-Drug interaction

↑ CNS depression with other CNS depressants including alcohol, antihistamines, opioid analgesics, and sedative/hypnotics.Concomitant use of kava-kava, valerian, or chamomile can ↑ CNS depression.

Route/Dosage

Oral (Adults) 800 mg 3–4 times daily.

Availability (generic available)

Tablets: 800 mg Cost: Generic — $409.39 / 100

Nursing implications

Nursing assessment

  • Assess for pain, muscle stiffness, and range of motion before and periodically during therapy.
  • Geriatric: Assess geriatric patients for anticholinergic effects (sedation and weakness).
  • Lab Test Considerations: Monitor hepatic function tests closely in patients with pre-existing liver damage.
    • May cause false-positive Benedict’s tests.

Potential Nursing Diagnoses

Acute pain (Indications)
Impaired bed mobility (Indications)
Risk for injury (Side Effects)

Implementation

  • Provide safety measures as indicated. Supervise ambulation and transfer.
  • Oral: Administer 3–4 times daily.

Patient/Family Teaching

  • Instruct patient to take medication as directed. Take missed doses within 1 hr; if not, return to regular dosing schedule. Do not double doses.
  • Encourage patient to comply with additional therapies prescribed for muscle spasm (rest, physical therapy, heat).
  • Medication may cause dizziness, drowsiness, and blurred vision. Advise patient to avoid driving and other activities requiring alertness until response to drug is known.
  • Instruct patient to make position changes slowly to minimize orthostatic hypotension.
  • Advise patient to avoid concurrent use of alcohol and other CNS depressants while taking this medication.
  • Instruct patient to notify health care professional if skin rash or yellowish discoloration of the skin or eyes occurs.
  • Emphasize the importance of routine follow-up exams to monitor progress.

Evaluation/Desired Outcomes

  • Decreased musculoskeletal pain and muscle spasticity.
    • Increased range of motion.

Skelaxin™

A centrally acting muscle relaxant.
 
Adverse effects
Nausea, vomiting, gastrointestinal upset, drowsiness, dizziness, headache, irritability, rash, pruritus, leukopenia, haemolytic anaemia, jaundice.