A Guide for Methocarbamol Interactions: What to Avoid?

Last Updated: June 6, 2024

David Levin Reviewed by David Levin
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The increasing opioid epidemic in the U.S. has led the medical community to find non-opioid alternatives for the management of skeletal muscle conditions.

Centrally acting skeletal muscle relaxants (SMRs), such as methocarbamol (Robaxin), have become viable options for acute muscle spasms and lower back pain. They are also off-label for neuropathic pain, chronic noncancer pain, temporomandibular disorder pain, and numerous nonpain conditions.

Yet, considering the adverse drug events associated with SMRs, such as dizziness and drowsiness that may cause unintentional traumatic injuries, you may wonder: How safe is methocarbamol? What happens during a combination of Robaxin and tramadol? Continue reading to learn more about methocarbamol interactions and how to ensure a safe treatment plan.

Methocarbamol Overview

Previously known under the brand name Robaxin®, methocarbamol is a centrally-acting skeletal muscle relaxant frequently prescribed for managing acute, painful musculoskeletal conditions.

Classified as a carbamate derivative, its exact mechanism of action still needs to be fully understood. Still, it is believed to involve general central nervous system (CNS) depression, reducing muscle spasticity without directly interfering with muscle function. Approved by the FDA in 1957, methocarbamol can be found in both oral and injectable forms.

While highly effective for pain management, the package insert mentions methocarbamol side effects that you should take into account, such as:

  • Seizures (severe)
  • Leukopenia (severe)
  • Cholestatic jaundice (severe)
  • Sedation or drowsiness
  • Dizziness
  • Headache
  • Confusion
  • Amnesia
  • Falls
  • Syncope
  • Diplopia (double vision)
  • Dyspepsia (indigestion)
  • Nausea
  • Vomiting
  • Metallic taste

Methocarbamol Interactions: What to Avoid?

Although highly contraindicated, polypharmacy is prevalent, especially during skeletal muscle relaxant use. Data from 2016 highlights that in two-thirds of ambulatory care visits in the U.S. where SMR therapy was continued, there was concurrent opioid use.

This scenario increases the concern for unintentional traumatic injuries and other health issues due to the complex methacarbamol drug interactions that may occur, which can potentially exacerbate the intrinsic risks associated with SMRs.

If you are wondering: Can I take methocarbamol and gabapentin together? Can you take Tylenol and Robaxin? Below is a list of drug categories to answer your questions when you are being treated with methocarbamol:

Central Nervous System (CNS) Depressants

The concurrent use of methocarbamol with other CNS depressants (medications that slow down the central nervous system) can intensify sedative and depressant effects, leading to increased drowsiness, dizziness, notably slowed or difficult breathing, and impaired cognitive and motor function.

This combined effect can significantly impair a person’s ability to perform tasks requiring alertness, such as driving or operating machinery.

Examples of CNS depressants include:

Methocarbamol Interactions with Alcohol

The combination of alcohol and methacarbamol is contraindicated because acute alcohol intoxication along with carbamate use can cause combined central nervous system depression due to the additive sedative-hypnotic effects of these substances.

Taking methocarbamol with alcohol can worsen the side effects of both substances, leading to:

  • Severe drowsiness or dizziness
  • Slurred speech
  • Slow or shallow breathing
  • Confusion
  • Memory problems

This combination can impair your motor skills and judgment, making activities like driving or operating machinery extremely dangerous. Also, combining alcohol and methocarbamol increases the risk of overdose. Symptoms of overdose can include extreme drowsiness, confusion and lack of coordination, loss of consciousness, or even respiratory failure.

Methocarbamol Interactions with Weed

Marijuana is known to act as both a stimulant and a depressant, depending on the dose, strain, and individual physiological responses. When marijuana is used in conjunction with methocarbamol, there can be a similar additive effect as alcohol.

Weed and methocarbamol can cause:

  • Intensified drowsiness
  • Dizziness
  • Cognitive impairments (decreased attention, impaired memory, and slowed reaction times)
  • Malaise
  • Dysphemia (speech defect in females)
  • Arthralgia (in males)
  • Dry mouth
  • Nausea
  • Vomiting
  • Memory loss
  • Seizure

It’s safe to remember that using multiple substances that affect the CNS increases the risk of developing a dependence on one or both of them. This can lead to complications in managing your health and medication regimen.

Anticholinergic Agents

Anticholinergics are a class of medications that block the action of the neurotransmitter acetylcholine. Acetylcholine mediates many bodily functions, including muscle movement, mood and memory, urination, and saliva production.

Methocarbamol may have additive anticholinergic effects when used with other drugs that possess anticholinergic properties. This can increase the risk of dry mouth, urinary retention, constipation, and confusion, particularly in the elderly.

Examples of anticholinergic agents include:

  • Antihistamines (i.e., diphenhydramine, hydroxyzine)
  • Tricyclic antidepressants (i.e., amitriptyline, nortriptyline)
  • Antiparkinson drugs (i.e., benztropine, trihexyphenidyl)

Medications that Lower Seizure Threshold

A seizure threshold refers to the minimum stimulation level required to trigger a seizure. Since methocarbamol depresses the central nervous system, this depression can theoretically make the brain more susceptible to seizures. Caution is advised when used with other medications that can also lower the seizure threshold.

Examples include:

  • Antipsychotics (i.e., clozapine and chlorpromazine)
  • Antidepressants (i.e., tricyclic and selective serotonin reuptake inhibitors (SSRIs) like bupropion)
  • Stimulants (i.e., amphetamines and methylphenidate)
  • Antibiotics (i.e., fluoroquinolones)

Tramadol and Robaxin

Using tramadol, an opioid pain reliever, together with Robaxin, may depress the central nervous system (CNS), potentially leading to enhanced drowsiness, dizziness, reduced motor skills, and impaired cognitive functions.

Since tramadol has specific additional risks such as tachycardia, hypertension, seizures, serotonin syndrome, and reports of mania activation, tramadol, and methocarbamol together could increase the risk of seizures, especially in those with a history of seizures or on high doses of tramadol.

Methocarbamol Interactions with Non-steroidal anti-inflammatory drugs (NSAIDs)

Research on this interaction is limited, with mixed results. In one study, this combination appears to offer little therapeutic benefits, and in another, high doses of both NSAIDs and muscle relaxants are required to achieve the best results. However, can you take Robaxin with Tylenol?

Methocarbamol Interactions with Tylenol

Acetaminophen, commonly known as Tylenol, is often paired with Robaxin for added effectiveness in managing pain. Robaxin helps relax tense muscles, while acetaminophen acts as a pain reliever. This combination of methocarbamol and Tylenol is frequently seen in Canada and can be found in combination medications like Robaxacet, available in both branded and generic forms.

The side effects of combining methocarbamol and Tylenol are typically mild but may include drowsiness, dizziness, and light-headedness. Tylenol and methocarbamol can generally be taken together safely under medical supervision.

Methocarbamol Interactions with Ibuprofen

Methocarbamol helps reduce muscle spasms, while ibuprofen reduces inflammation and pain. Together, they can provide more comprehensive relief for conditions involving muscle pain and inflammation, such as strains, sprains, or back pain.

There are no significant direct pharmacological interactions between methocarbamol and ibuprofen, and it is common for healthcare providers to prescribe Robaxin and ibuprofen at the same time.

Other Important Methocarbamol Drug Interactions

Interactions between Methocarbamol and other popular drugs, like anticonvulsants and benzodiazepines, have also been noted. Can you take gabapentin and methocarbamol together? What about Xanax? Because these interactions can be common, it is important to know the associated risks.

Gabapentin and Methocarbamol

Gabapentin was initially used for muscle relaxation and spasm relief. Currently, it is primarily used for epilepsy, seizures, and nerve pain. Both drugs can help with pain relief, especially for lower back issues.

However, combining Robaxin and gabapentin can lead to serious side effects like extreme drowsiness, confusion, and even depression or suicidal thoughts, particularly in older adults. Methocarbamol and gabapentin side effects vary by individual, and interactions with other drugs can change Gabapentin’s anticonvulsant properties.

Methocarbamol Interactions with Xanax

Xanax, a medication prescribed for stress and anxiety, falls under the category of benzodiazepines and contains Alprazolam as its active ingredient.

Both Xanax and Robaxin affect the brain but in different ways. Xanax calms the central nervous system, while Robaxin blocks pain signals. When taken together, their sedative effects can become stronger, making this combination potentially dangerous.

When to Seek a Doctor

Here are some situations where you should seek a doctor’s guidance regarding your methocarbamol use:

  • If you have pre-existing medical conditions or are taking other medications, you are pregnant/breastfeeding.
  • If your muscle pain or stiffness doesn’t improve or if it worsens.
  • If the side effects of methocarbamol become severe.
  • If you are unsure about potential methocarbamol drug interactions with other medications you are taking.
  • If your methocarbamol dosage is unclear and you need further guidance.

Methocarbamol Interactions − Bottom Line

Given the limited population-based evidence on muscle relaxant drug interactions, the increasing use of these medications, and their frequent combination with other CNS-depressing drugs, especially among older adults, it is crucial to take precautions when combining medications.

Always consult your healthcare provider before combining methocarbamol with other medications. Monitor for adverse effects, avoid alcohol and other CNS depressants, follow dosage instructions, and avoid high-risk activities. For better outcomes, combine treatment with rest and physical therapy.

Remember to seek immediate medical attention if severe side effects occur or if addiction is suspected.

People Also Ask

Can you take Methocarbamol with Gabapentin?

Methocarbamol interactions with gabapentin can significantly worsen side effects like drowsiness, confusion, and even depression, especially for older adults. Additionally, interactions can alter gabapentin’s effectiveness for seizures.

Can Robaxin and tramadol be taken together?

The tramadol and methocarbamol combination can intensify drowsiness and dizziness, impair cognitive functions, and potentially increase seizure risks, especially in individuals with a seizure history.

Does methocarbamol make you sleepy?

Yes, methocarbamol can cause drowsiness as a common side effect. Avoid activities requiring alertness, such as driving or operating machinery.


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Published on: January 29th, 2020

Updated on: June 6th, 2024

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