Metaxalone Dosage

Medically reviewed by Drugs.com. Last updated on Mar 29, 2024.

Applies to the following strengths: 400 mg; 800 mg; 640 mg

Usual Adult Dose for Muscle Spasm

640 mg or 800 mg orally 3 to 4 times a day

Comments:

Two 400 mg tablets or one 800 mg tablet are not substitutable on a mg-to-mg basis with 640 mg tablets. It is appropriate to switch:
Only in patients who have been taking 640 mg tablets on an empty stomach
Stop 640 mg tablets three times a day and start two 400 mg or one 800 mg three times a day on an empty stomach, OR stop 640 mg tablets four times a day and start two 400 mg or one 800 mg tablets four times a day on an empty stomach.
Do not switch in patients taking this drug with food.

Use: Painful musculoskeletal conditions as an adjunct to rest, physical therapy, and other measures

Children 13 years and older:
640 mg or 800 mg orally 3 to 4 times a day

Comments:

Two 400 mg tablets or one 800 mg tablet are not substitutable on a mg-to-mg basis with 640 mg tablets. It is appropriate to switch:
Only in patients who have been taking 640 mg tablets on an empty stomach
Stop 640 mg tablets three times a day and start two 400 mg or one 800 mg three times a day on an empty stomach, OR stop 640 mg tablets four times a day and start two 400 mg or one 800 mg tablets four times a day on an empty stomach.
Do not switch in patients taking this drug with food.

Use: Painful musculoskeletal conditions as an adjunct to rest, physical therapy, and other measures in patients 13 years of age and older

Mild to moderate renal dysfunction: Use with caution
Severe renal dysfunction: Contraindicated

Mild to moderate liver dysfunction: Use with caution
Severe liver dysfunction: Contraindicated

CONTRAINDICATIONS:

Safety and efficacy have not been established in patients younger than 13 years.

Consult WARNINGS section for additional precautions.

Data not available

Administration advice:

Storage requirements:

Store at 20C to 25C (68F to 77F), with excursions permitted to 15C to 30C (59F to 86F)

General:

Deaths by deliberate or accidental overdose have occurred with this drug, particularly in combination with antidepressants, and in combination with alcohol.

Monitoring:

CNS symptoms and signs of serotonin syndrome, respiratory depression, or excessive sedation
Report suspected adverse reactions to www.fda.gov/medwatch

Patient advice:

Read the Patient Information and Instructions for Use.
This drug may impair mental and/or physical abilities required for performance of hazardous tasks, such as operating machinery or driving a motor vehicle, especially when used with alcohol or other CNS depressants.