metaxalone

Absorption: Well absorbed following oral administration.

Distribution: Unknown.

Metabolism/Excretion: Mostly metabolized by the liver; metabolites excreted in urine.

Half-Life: 2–3 hr.

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
PO	1 hr	2 hr	4–6 hr

Contraind./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;
OB: Safety not established in pregnancy;
Lactation: Safety not established in breastfeeding;
Pedi: Children ≤12 yr (safety and effectiveness not established);
Geri: Appears on Beers list. ↑ risk of anticholinergic adverse reactions, sedation, and fractures in older adults. Avoid use in older adults.

Adv. Reactions/Side Effects ⬆ ⬇

GI: nausea, anorexia, dry mouth, GI upset, vomiting

GU: urinary retention

Neuro: dizziness, drowsiness, confusion, headache, irritability, nervousness

Misc: SEROTONIN SYNDROME

Interactions ⬆ ⬇

Drug-drug:

↑CNS depression with other CNS depressants including alcohol, antihistamines, opioid analgesics, and sedative/hypnotics.
Drugs that affect serotonergic neurotransmitter systems, including SSRIs, tricyclic antidepressants, SNRIs, MAOIs, fentanyl, buspirone, tramadol, amphetamines, linezolid, methylene blue, and triptans, ↑ risk of serotonin syndrome

Drug-Natural Products:

Concomitant use of kava-kava, valerian, or chamomile can ↑ CNS depression.

Route/Dosage ⬆ ⬇

PO (Adults ): 800 mg 3–4 times daily.

Availability ⬆ ⬇

(Generic available)

Tablets: 400 mg; 800 mg

Assessment ⬆ ⬇

Assess for pain, muscle stiffness, and range of motion before and periodically during therapy.
Geri: 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.

Implementation ⬆ ⬇

Provide safety measures as indicated. Supervise ambulation and transfer.
PO: 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.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding.
Emphasize the importance of routine follow-up exams to monitor progress.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇