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Carbacot Side Effects

Generic Name: methocarbamol

Note: This document contains side effect information about methocarbamol. Some of the dosage forms listed on this page may not apply to the brand name Carbacot.

For the Consumer

Applies to methocarbamol: oral tablet

Other dosage forms:

Along with its needed effects, methocarbamol (the active ingredient contained in Carbacot) 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 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

Get emergency help immediately if any of the following symptoms of overdose occur while taking methocarbamol:

Symptoms of Overdose

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

Some side effects of methocarbamol 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:

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 (the active ingredient contained in Carbacot) 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"


Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.