Key takeaways
Methocarbamol is a muscle relaxant that can relieve muscle spasms, muscle pain, and stiffness. It may be given as an oral tablet, an injection, or as an oral suspension under the brand name Atmeksi.
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, metabolism, health conditions, and other medications, can affect how quickly methocarbamol works for you.
Methocarbamol is a generic drug that is used to treat muscle spasms, pain, and discomfort caused by short-term musculoskeletal conditions. 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 reach its peak effect. This article covers methocarbamol’s onset, duration, how long it remains in the body, and what to do if it does not seem to be working.
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. The effects last about four to six hours, on average.
Various factors affect how quickly methocarbamol is processed in the body. 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.
Methocarbamol onset and duration timeline |
|
|---|---|
| Time after taking methocarbamol | What to expect |
| About 30 minutes | Effects may begin |
| 1 to 2 hours | Peak effect |
| Several hours | Effects gradually wear off; the dose typically lasts about 4–6 hours |
| After effects wear off | Even after the noticeable effects have ended, the drug can remain in the body for up to about 10 hours |
Because methocarbamol is metabolized relatively quickly and is fairly short-acting, healthcare providers may prescribe it multiple times per day, depending on the condition and dosage. “Some people take it only as needed, and they may only take it at a certain time of day when they experience symptoms,” Marchese says. “And if a person does not want to be drowsy during the day, they may opt to only take it at night.”
Your healthcare provider will determine the methocarbamol dose that is appropriate for your condition and symptoms. It’s important to follow the dosing instructions and take your medication exactly as directed.
How long do the effects of methocarbamol last?
The effects of a dose of methocarbamol typically last about four to six hours. Based on how the body processes methocarbamol, healthcare providers may prescribe it three or four times daily to account for this. Your healthcare provider will tell you how often you should take methocarbamol, and it’s important to stick to those instructions. You should not take methocarbamol more frequently or at higher doses than prescribed. If you find that it is not working for you, check in with your healthcare provider for medical advice.
It is also important to note that even though the effects of a dose may wear off after four to six hours, the drug can remain in your system for a few hours longer.
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How long does methocarbamol stay in your system?
A single dose of methocarbamol generally remains in your system for up to 10 hours. This duration is determined by the drug’s half-life: the time required for your body to eliminate half of the administered dose. Assuming no additional doses are ingested, it typically requires four to five half-lives for a medication to be almost entirely cleared from the body.
With a methocarbamol half-life of one to two hours, a dose is mostly eliminated within 10 hours. However, individual clearance rates can differ based on personal factors like age, as well as kidney or liver function.
Even though methocarbamol can linger in the body for up to 10 hours, noticeable therapeutic effects do not last that long. A single dose typically provides active relief for only four to six hours.
What affects how long methocarbamol stays in your system?
Various factors can affect how the body processes methocarbamol. Drug metabolism varies from person to person and can be influenced by genetics and age, as well as coexisting conditions such as chronic liver disorders. Interactions with other medications may also affect how a person responds to methocarbamol.
- Age: Methocarbamol’s prescribing information notes that older adults may have a slightly longer half-life, meaning that it may take them a little longer to eliminate the medicine from their bodies.
- Liver or kidney function: People with certain liver or kidney problems may eliminate methocarbamol more slowly from their bodies.
- Other medications: Taking methocarbamol along with medications or substances (such as alcohol or cannabis) that cause central nervous system depression can increase side effects like dizziness and drowsiness.
What if methocarbamol isn’t working?
Methocarbamol typically starts working within about 30 minutes, with peak effects usually occurring in one or two hours. But what if you take a dose of methocarbamol and after a few hours, you are in just as much pain as before?
While it may seem helpful to take extra doses or higher doses of methocarbamol, this is not advised. It is important to only adjust your dose under the guidance of your healthcare provider. Individual response to the drug may vary, and methocarbamol may not relieve every type or cause of pain.
If you are taking methocarbamol and your symptoms are worsening or not improving, contact your healthcare provider for medical advice. They may advise changing the dose or trying a different drug. They may also suggest other measures, such as ice, physical therapy, or rest. Always follow the advice of your healthcare provider.
How methocarbamol works
It’s not known exactly how this medicine works. It is believed that methocarbamol relaxes the muscles in the body through its effects on 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 may help relieve pain associated with muscle spasms.
When should you take methocarbamol?
Methocarbamol oral tablets are available in 500 mg, 750 mg, and 1000 mg. It is also available as an injectable solution. Dosing schedules vary, and patients should take methocarbamol exactly as prescribed. There is no specific best time of the day to take methocarbamol, and you can take it with or without food. Methocarbamol is generally prescribed three or four times daily. You can ask your healthcare provider about timing, because they may have a more specific recommendation based on your schedule. You should avoid driving until you know how methocarbamol affects you.
Also, a 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,” says Jerome Enad, MD, an orthopedic surgeon in Pensacola, Florida. 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.
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 safety and side effects
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.
Methocarbamol may affect your ability to perform dangerous tasks like operating machinery or driving. Do not drive or operate machinery while taking methocarbamol until you know how this drug affects you.
Keep in mind that taking other drugs with methocarbamol that cause sedation may increase the risk of sleepiness and unsteadiness. This includes some over-the-counter medications, such as certain antihistamines.
Methocarbamol side effects
Methocarbamol has effects on the central nervous system (CNS). Common side effects may include drowsiness and dizziness. Other reported side effects include upset stomach, blurred vision, fever, and discoloration of the urine.
If you experience symptoms of an allergic reaction while taking methocarbamol, get emergency medical attention. Signs and symptoms may 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 the risks and benefits of methocarbamol with your healthcare provider.
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, other CNS depressants are among the important interactions to be aware of. Examples may include sleeping medications, barbiturates, benzodiazepines, and opioids. Methocarbamol can also interact with alcohol and cannabis, so it’s best to avoid these while taking methocarbamol.
Certain medical conditions, such as liver disease, kidney impairment, or a seizure disorder, could affect whether methocarbamol is appropriate for you. Liver or kidney problems may affect how the body processes methocarbamol. People with a history of seizures should not use injectable methocarbamol.
Tell your healthcare provider if you are pregnant, planning to become pregnant, or breastfeeding. Methocarbamol is typically only used in pregnancy if the healthcare provider determines that the benefits outweigh the risks. There is not enough known about methocarbamol and breastfeeding, so if you are breastfeeding, you can discuss risks versus benefits with your healthcare provider.
Expert takeaway
“Methocarbamol starts working in about 30 minutes, with peak effects occurring by one or two hours,” says Karen Berger, Pharm.D., member of the SingleCare Medical Review Board. “A dose of methocarbamol typically lasts about four to six hours, but individual responses may vary. It’s important to take methocarbamol exactly as prescribed by your healthcare provider. If you find that the medication is not giving you enough relief, check in with your healthcare provider for medical advice rather than increasing the dose on your own.”
FAQs about how long methocarbamol takes to work
How long does methocarbamol 500 mg take to work?
Whether you are taking methocarbamol 500 mg or another dose, it should take about 30 minutes to start working and reach maximum effects in one to two hours. The amount of time it takes to work does not depend on the dose.
Does methocarbamol make you sleepy?
Methocarbamol can cause drowsiness and dizziness. Avoid alcohol and do not drive until you know how methocarbamol affects you. Also, be sure to review any potential drug interactions with your healthcare provider because certain drugs may increase these side effects.
Can you take methocarbamol before bed?
Methocarbamol can be taken before bed if the timing works with the dosing schedule recommended by your healthcare provider. Methocarbamol may cause drowsiness, so some people prefer taking a dose closer to bedtime. However, if you take methocarbamol several times a day, follow your prescribed dosing schedule and ask your healthcare provider if you have any questions or concerns.
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