Metaxalone Side Effects

Medically reviewed by Drugs.com. Last updated on Feb 23, 2025.

Applies to metaxalone: oral tablet.

Common side effects of metaxalone

Some side effects of metaxalone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

• drowsiness
• irritability
• stomach or bowel upset

Serious side effects of metaxalone

Along with its needed effects, metaxalone may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking metaxalone:

Incidence not known

• agitation
• back, leg, or stomach pains
• black, tarry stools
• bleeding gums
• chest pain
• chills
• clay-colored stools
• confusion
• cough
• dark urine
• diarrhea
• difficulty in breathing or swallowing
• dizziness
• fast heartbeat
• fever
• general body swelling
• headache
• hives, itching, skin rash
• loss of appetite
• nausea
• nosebleed
• painful or difficult urination
• pale skin
• poor coordination
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• redness of the skin
• restlessness
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• stomach pain
• sweating
• swelling of the face, throat, or tongue
• swollen glands
• talking or acting with excitement you cannot control
• tightness in the chest
• trembling or shaking
• twitching
• unpleasant breath odor
• unusual bleeding or bruising
• unusual tiredness or weakness
• vomiting
• vomiting of blood
• yellowing of the eyes or skin

For healthcare professionals

Applies to metaxalone: oral tablet.

General adverse events

The most frequent reactions were drowsiness, dizziness, headache, irritability, nausea, vomiting and gastrointestinal upset.^[Ref]

Gastrointestinal

• Frequency not reported: Nausea, vomiting, gastrointestinal upset^[Ref]

Hematologic

• Frequency not reported: Leukopenia, hemolytic anemia^[Ref]

Hepatic

• Frequency not reported: Jaundice^[Ref]

Hypersensitivity

• Frequency not reported: Anaphylaxis, hypersensitivity reaction, rash (with or without pruritus)^[Ref]

Nervous system

• Frequency not reported: Serotonin syndrome, drowsiness, dizziness, headache^[Ref]

Other

• Frequency not reported: False-positive Benedict's tests (due to an unknown reducing substance)^[Ref]

A glucose-specific test may be used to differentiate findings.^[Ref]

Psychiatric

• Common (1% to 10%): Nervousness, irritability^[Ref]

Further information

Metaxalone side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer