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Drug Info

How long does it take for methocarbamol to work?

This medicine works quickly to relieve muscle aches and pains
Rosemary Black
By | Feb. 11, 2025 Medically reviewed by Anne Jacobson, MD, MPH
An hourglass and a pill bottle: How long does it take for methocarbamol to work?

Key takeaways

  • Methocarbamol is a muscle relaxant that can relieve muscle spasms, muscle pain, and stiffness. It may be given as an oral tablet or an injection. 

  • Methocarbamol starts to work in about 30 minutes and reaches its peak effect between one and two hours after taking it.

  • Various factors, such as your age, affect how you metabolize methocarbamol and how quickly it works for you.

  • Taking this medicine with alcohol or with other sedatives can increase the risk of dangerous sedation and accidental injuries. Older adults are at a higher risk of injury due to the drowsiness and dizziness that can occur with methocarbamol.

In this article:

Methocarbamol is a generic drug that is used to treat muscle spasms, pain, and discomfort caused by short-term musculoskeletal conditions. Healthcare providers generally prescribe methocarbamol to be used along with physical therapy, rest, and other treatments. 

Methocarbamol has sedative effects and is only meant to be taken for short-term relief.

After taking an oral dose, you may feel its effects within about half an hour, although it may take up to two hours to work, depending on various factors. Read on to learn more about what you can expect when taking methocarbamol and when to expect relief from muscle pain.

How methocarbamol works

It’s not known exactly how this medicine works. It is believed that methocarbamol relaxes the muscles in the body by depressing the central nervous system (CNS). 

“Methocarbamol doesn’t directly affect the muscles through nerve transmission,” says Talisa M. Marchese, Pharm.D., a board-certified psychiatric pharmacist and clinical associate professor in the Department of Pharmacy Practice at D’Youville University in Buffalo, New York. “But it has a depressant effect on the central nervous system, which reduces muscle spasms. This skeletal muscle relaxation reduces the pain caused by the muscle spasm.” While methocarbamol is not a pain medication per se, it decreases a person’s perception of pain.

How long does it take methocarbamol to work?

It could take about 30 minutes for methocarbamol to start working, reaching its peak effect within one to two hours after taking it, according to Marchese. Jerome Enad, MD, an orthopedic surgeon in Pensacola, Florida, adds that the entire effect should last three to four hours. 

However, various factors affect how quickly methocarbamol works for someone. It all depends on your drug metabolism rate, which can vary. A person’s drug metabolism depends on factors such as genetics and age, as well as any coexisting conditions such as chronic liver disorders. It is also affected by interactions with other drugs. 

Because methocarbamol is metabolized relatively quickly and is fairly short-acting, healthcare providers typically recommend taking it three to four times a day, according to Marchese. “Some people take it only as needed, and they may only take it at a certain time of day when they experience symptoms,” she says. “And if a person does not want to be drowsy during the day, they may opt to only take it at night.”

What to consider before taking methocarbamol

Methocarbamol is not classified as a controlled substance like some other muscle relaxants, but there are still important things to consider before taking it. “Any of the muscle relaxants can cause sedation, and patients should be aware of this as a side effect with methocarbamol,” Dr. Enad says.

Before driving while taking methocarbamol, become familiar with how this drug affects you. And if you do become drowsy while taking it, don’t drive until four to six hours have passed since your last dose.

Keep in mind that taking other drugs with methocarbamol that cause sedation may increase the risk of sleepiness and unsteadiness. This includes over-the-counter medications, such as antihistamines. 

If you forget to take methocarbamol, take the missed dose as soon as you remember it. But if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Methocarbamol side effects

This drug has a depressant effect on the CNS. There are significant side effects that may include drowsiness, dizziness, confusion, and risk of accidental injury (e.g., falls, especially in older adults). Other side effects may include an upset stomach, blurred vision, a fever, or discoloration of urine. Take methocarbamol with food to avoid stomach upset, and avoid alcohol and other sedatives while taking it.

If you experience a rash or itching while taking methocarbamol, call your healthcare provider immediately, Dr. Enad advises. This could be a sign of an allergic reaction. Other symptoms of an allergic reaction to methocarbamol include:

  • Hives
  • Swelling of the face, lips, mouth, or throat
  • Low blood pressure
  • Weak pulse
  • Trouble breathing

If you are 65 years of age or older, discuss with your healthcare provider the risks and benefits of taking methocarbamol. Older adults usually should not take this medicine as it is not as safe or as effective as other medications that can be used to treat symptoms.

Methocarbamol warnings and interactions

As with any prescription medicine, methocarbamol should be taken under the supervision of a healthcare provider. While various drugs can interact with methocarbamol, it’s other CNS depressants that are the most concerning interactions to be aware of. Examples include sleeping pills, barbiturates, benzodiazepines, and opioids. 


Certain medical conditions, such as liver disease, kidney impairment, or a seizure disorder, could impact whether methocarbamol will be safe for you. And since it is unknown whether methocarbamol is present in breast milk, breastfeeding women should exercise caution and check with their healthcare provider before taking this drug.

Proper use of methocarbamol

Methocarbamol oral tablets are available in two strengths: 500 mg and 750 mg. It is also available as a 100 mg/mL injectable solution, as brand-name Robaxin. The standard dosage is between 1,000 mg and 2,000 mg every six hours. However,  your prescribed dosage depends on why you are taking it, what other health conditions you have, and what additional medications you take. The general recommendation is that muscle relaxants such as methocarbamol should only be used temporarily —for a few days or weeks, according to Marchese.

“Your doctor should guide you on side effects and allergic reactions to look out for,” Dr. Enad says. He emphasizes the importance of communicating with your healthcare provider while taking methocarbamol so they can monitor your side effects and adjust dosage as needed. Never adjust the dosage on your own.