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Methocarbamol Side Effects

For the Consumer

Applies to methocarbamol: oral tablet

Other dosage forms:

In addition to its needed effects, some unwanted effects may be caused by methocarbamol. In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking methocarbamol:

Incidence not known:
  • Black, tarry stools
  • changes in skin color
  • chest pain or discomfort
  • chills
  • clay-colored stools
  • cough
  • dark urine
  • diarrhea
  • difficulty in swallowing
  • dizziness
  • fast heartbeat
  • feeling of warmth
  • fever
  • headache
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • lightheadedness, dizziness, or fainting
  • loss of appetite
  • loss of bladder control
  • loss or problems with memory
  • nausea
  • numbness or tingling of face, hands, or feet
  • pain, tenderness, or swelling of foot or leg
  • painful or difficult urination
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redness and soreness of the eyes
  • redness of the face, neck, arms, and occasionally, upper chest
  • skin rash
  • sleepiness
  • slow or irregular heartbeat
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • stomach pain
  • sweating
  • swollen glands
  • tightness in the chest
  • total body jerking
  • unpleasant breath odor
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vomiting of blood
  • yellow eyes or skin

If any of the following symptoms of overdose occur while taking methocarbamol, get emergency help immediately:

Symptoms of overdose:
  • Loss of consciousness
  • shaking or jerking of one area or side of the body

Minor Side Effects

Some of the side effects that can occur with methocarbamol may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Incidence not known:
  • Belching
  • double vision
  • drowsiness
  • feeling of constant movement of self or surroundings
  • heartburn
  • indigestion
  • mood or mental changes
  • sensation of spinning
  • stomach discomfort, upset, or pain
  • trouble sleeping
  • uncontrolled eye movements

For Healthcare Professionals

Applies to methocarbamol: injectable solution, oral tablet


Cardiovascular side effects have included syncope, hypotension, and bradycardia.[Ref]

Nervous system

Nervous system side effects have included dizziness, lightheadedness, vertigo, headache, drowsiness, fainting, and mild muscular incoordination. Convulsions have been reported with intravenous administration, especially in patients with a history of epilepsy.[Ref]


Dermatologic side effects have included urticaria, pruritus, rash, sloughing, thrombophlebitis, and pain at the injection site.[Ref]


Ocular side effects have included blurred vision, conjunctivitis, nystagmus, and diplopia.[Ref]


Respiratory side effects have included nasal congestion, bronchospasm, and anaphylaxis.[Ref]


Gastrointestinal side effects have included gastrointestinal upset, anorexia, and adynamic ileus.[Ref]


Other side effects have included metallic taste and fever.

Effects on lab tests have included a possible color interference in certain screening tests for 5-hydroxyindoleacetic acid (5-HIAA) and vanillylmandelic acid (VMA).[Ref]


Hematologic side effects have included hemolysis, particularly with intravenous injection.[Ref]


Methocarbamol vials for injection contain polyethylene glycol 300 (PEG 300). Larger amounts of PEG 300 can increase preexisting renal acidosis and urea retention in patients with renal insufficiency.[Ref]

Renal side effects including urine discoloration (black, blue, brown, or green) have been reported after oral administration in some patients.[Ref]


General side effects have included angioneurotic edema.[Ref]


1. "Product Information. Robaxin Injectable (methocarbamol)." Whitehall-Robbins, Madison, NJ.

2. "Multum Information Services, Inc. Expert Review Panel"


Not all side effects for methocarbamol may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.