Methocarbamol dosage, forms, and strengths

Medically reviewed by Anne Jacobson, MD, MPH
Board-Certified Family Physician
Written by SingleCare Team
Updated Oct 8, 2025  •  Published Aug 2, 2021
Datos Verificados
In this article:

Key takeaways

  • The standard methocarbamol dosage for painful muscle spasms in adults and children 16 years of age or older is 1,000 mg taken three times daily.

  • The max dose of methocarbamol is 8,000 mg/day.

  • Methocarbamol is available as tablets and injections.

  • Methocarbamol should be taken evenly spaced throughout the day, with or without food.

  • Do not take methocarbamol if you have had a reaction to methocarbamol.

Methocarbamol is a generic prescription skeletal muscle relaxant. The brand-name version is Robaxin. Doctors use methocarbamol along with rest and physical therapy to treat painful muscle spasms due to musculoskeletal conditions like back or neck problems. Most people take methocarbamol as oral tablets. The daily dosing schedule varies, but doses are typically taken every six hours.

Methocarbamol forms and strengths

Methocarbamol may be taken by mouth or administered as an intramuscular or intravenous injection. It comes in only a few strengths, including:

  • Tablets: 500 mg, 750 mg

  • Injection: 100 mg per mL

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Detailed methocarbamol dosage chart for adults
Indication Starting dose Maintenance dose Maximum dose
Muscle spasms 1,500 mg by mouth every 6 hours for 2–3 days 1,000 mg by mouth every 6 hours OR 1,500 mg (2, 750 mg tablets) every 8 hours OR 750 mg every 4 hours 8,000 mg daily for start dose
Tetanus 1,000–3,000 mg by IV once 1,000–2,000 mg by NG tube (crushed tablets) or IV every 6 hours 24 g per day by NG tube or intravenous injection

Detailed methocarbamol dosage chart for children
Indication Weight/age Recommended dose (tablet) Recommended dose (injection)
Tetanus Children younger than 16 years of age N/A 15 mg per kilogram of the child’s body weight per dose, given every 6 hours for up to 3 days
Muscle spasms Children 16 years of age or older 1,000 mg every 6 hours, as needed N/A

Methocarbamol dosage for musculoskeletal pain

Methocarbamol is FDA-approved to treat active episodes of musculoskeletal pain, such as back pain, neck pain, herniated disk, spinal injury, muscle strains, post-operative muscle pain, or similar problems. Although its exact mechanism of action is not well understood, methocarbamol is a centrally acting skeletal muscle relaxant that relieves involuntary muscle spasms. 

The initial doses are high (1,500 mg four times daily) but are reduced to a lower maintenance dose after two or three days. The maintenance dose schedule will depend on the dosage strength (500 mg or 750 mg) prescribed and can range from three to six times daily. Because of the risk of abuse, serious side effects, or methocarbamol overdose, doctors tend to prescribe methocarbamol only in the short term.

Methocarbamol dosage for tetanus

Tetanus (“lockjaw”) is a life-threatening bacterial infection. The poison produced by the bacteria affects the nervous system, resulting in rigid muscles and an overactive involuntary nervous system, producing high blood pressure, racing heartbeats, sweating, and other problems. The standard treatment involves emergency airway procedures, tetanus antibodies, tetanus vaccine, and benzodiazepines to relax the muscles, slow down the nervous system, and provide sedation. Methocarbamol is not commonly used, but there are cases where it will be used as a muscle relaxant instead of benzodiazepines. If so, doctors start with a high-dose intravenous injection and switch to a nasogastric feeding tube as soon as possible.

Personalized dosing considerations

Dosing modifications for people with kidney or liver problems have not been specified. However, doctors are warned to be cautious about using methocarbamol in people with liver cirrhosis or severe kidney disease.

Methocarbamol safety info

Methocarbamol is a powerful medication that is safe for most people to take. The most common side effects of methocarbamol are drowsiness, dizziness, lightheadedness, stomach upset, nausea, and a metallic taste in the mouth. 

The most important thing to know about methocarbamol is that it can cause drowsiness, blurred vision, and impairment. People taking methocarbamol should be cautious about engaging in risky activities like driving or operating machinery.

It is never safe for methocarbamol to be taken by people who have had an allergic reaction to methocarbamol. The injections are never safe for people with known or suspected kidney dysfunction.

Older adults and people with renal impairment or liver disease can take methocarbamol without any dosage reduction, but they are at a higher risk for adverse reactions.

Doctors are cautious about using methocarbamol injections in people with seizure disorders or a latex allergy. The injections aren’t prohibited, but the healthcare provider may choose another treatment.

Methocarbamol may cause birth defects, especially if taken early in a pregnancy. It’s not prohibited, but doctors generally avoid it, particularly injections.

Healthcare professionals do not know if methocarbamol is safe to take while breastfeeding. Ask the prescriber for medical advice. 

Healthcare professionals do not know if methocarbamol is safe for children. It is not FDA-approved for use in pediatric patients except for tetanus

Methocarbamol’s most significant drug interactions involve drugs that make people sleepy (CNS depressants). These include opioids, benzodiazepines, sleeping pills, alcohol, and sedating supplements such as kava kava or valerian. These drugs and supplements can worsen the sedative effects of methocarbamol, so they should be avoided when taking methocarbamol unless they’re absolutely necessary.

How to take methocarbamol 

Most people take methocarbamol tablets. Healthcare providers administer injections in a clinic or hospital. Even when taking tablets, however, patients should be aware of a few special considerations:

  • Take this medicine as directed. Do not change the dose.

  • Understand the dosing schedule. Depending on the dosage strengths, doses may need to be taken every four, six, or eight hours.

  • Tablets can be taken without regard to food.

  • Tablets can be crushed and mixed with water for use in a nasogastric feeding tube.

  • Store methocarbamol tablets at room temperature in a tightly closed container.

Methocarbamol dosage FAQs

How long does it take methocarbamol to work? 

Methocarbamol tablets should begin providing pain relief within 30 minutes of taking a dose, and methocarbamol injections should produce pain relief within minutes. 

RELATED: How long does it take methocarbamol to work?

How long does methocarbamol stay in your system? 

Methocarbamol has a short half-life of only four to six hours, so it is eliminated from the body relatively quickly. It takes about 20–30 hours for the body to completely clear a single methocarbamol dose from the body.

What happens if I miss a dose of methocarbamol?

Ask the prescriber how to manage a missed dose. Typically, the prescriber will advise that a missed dose be taken as soon as it’s remembered unless it’s almost time for the next dose. However, doses are taken every six to eight hours—sometimes every four hours—so some prescribers may have more precise instructions. Do not take a double dose to make up for a missed dose.

What is the maximum dosage for methocarbamol?

For muscle spasms, the maximum adult dose of methocarbamol is 8,000 mg per day during the initial phase of treatment. 

How do I stop taking methocarbamol?

Methocarbamol usually doesn’t cause withdrawal symptoms, but pain may return within a few hours of the last dose. Methocarbamol is typically stopped without reducing the dose. However, long-term use or addiction may cause unpleasant adverse effects when the drug is stopped, but there are no tapering recommendations. 

What is the dosage of methocarbamol for pets?

Veterinarians use methocarbamol tablets or injections to relieve painful muscle spasms in a dog or cat, for instance, animals with intervertebral disc disease, muscle strains, injury, inflammation, or surgery. Veterinarians also use methocarbamol injections to reduce muscle spasms due to strychnine poisoning, snail bait poisoning, permethrin (flea collar) poisoning, fungal toxins, and tetanus. 

Injections will be administered by a veterinary professional. For more moderate conditions, the veterinarian will send the owner home with oral tablets. The standard maintenance oral dose is 66–132 mg/kg per day, divided into two or three daily doses. Doses may be lower for special conditions such as intervertebral disc disease. 

RELATED: Methocarbamol for dogs

Sources

Medically reviewed by Anne Jacobson, MD, MPH
Board-Certified Family Physician

Anne Jacobson, MD, MPH, is a board-certified family physician, writer, editor, teacher, and consultant. She is a graduate of University of Wisconsin School of Medicine and Public Health, and trained at West Suburban Family Medicine in Oak Park, Illinois. She later completed a fellowship in community medicine at PCC Community Wellness and a master's in Public Health at the University of Illinois-Chicago. She lives with her family near Chicago.

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