Muscle pain (such as lower back pain) and muscle spasms are very common problems, affecting millions of people. Muscle spasms and pain are often treated with muscle relaxants, such as methocarbamol, which repress the nervous system to provide temporary relief. Read on to learn more about the uses, side effects, and natural alternatives to methocarbamol.
Note: By writing this post, we are not recommending this drug. Some of our readers who were already taking the drug requested that we commission a post on it, and we are simply providing information that is available in the clinical and scientific literature. Please discuss your medications with your doctor.
What is Methocarbamol?
Methocarbamol is a synthetic drug used to treat muscle spasms. It works by relaxing the muscles and is commonly used to alleviate muscle pain. If used at an appropriate dosage, it does not have a sedative effect. However, at higher doses, it can suppress breathing – a potentially fatal toxic effect [1, 2].
Typically, muscle relaxers, such as methocarbamol, are used to treat two types of muscle spasms, ones associated with brain or spinal cord problems (such as spinal cord injury, cerebral palsy, multiple sclerosis, and stroke) and ones associated with the nerves (such as fibromyalgia, tension headaches, myofascial pain syndrome, and lower back or neck pain) .
Mechanism of Action
Although the exact mechanism of action of methocarbamol is not known, it is thought to involve repression of the nervous system by blocking signals from the spine. Methocarbamol (as a carbamate) may block an enzyme (acetylcholinesterase) that breaks down the neurotransmitter acetylcholine [4, 5, 6, 7].
Methocarbamol doesn’t directly affect the muscle contraction, the part of the body where brain cells interact with muscle fibers (motor end plate), or the part of the nerve cell that extends out (nerve fiber). However, it does increase the period of time that the muscle is relaxed, or unable to respond to subsequent signals from the nerves (refractory period) [8, 4].
Uses of Methocarbamol
1) Muscle Spasms
Methocarbamol (1,500 mg 4 times a day) was 60% effective at treating painful muscle spasms (double-blind randomized controlled trial). However, 30% of the untreated group also felt symptom relief (placebo effect) .
82% of patients with various neurological disorders and muscle spasms reported beneficial results from methocarbamol treatment (~3-6 g/day, case studies of 38 patients) .
However, methocarbamol was ineffective at relaxing muscles for patients with recently dislocated shoulders (double-blind randomized controlled trial) .
In addition, a study review determined there is limited evidence methocarbamol is an effective treatment .
2) Improves Lower Back Pain
Methocarbamol effectively treated lower back spasms and pain and immobility related to pain in 67% of the 98 patients (randomized controlled trial). 36% of the untreated group also felt symptom relief (placebo effect) .
A retrospective cohort study reported that 4-week treatment with methocarbamol improved lower back pain, disability caused by pain, and quality of life in 251 patients .
However, in a study with 200 patients, methocarbamol did not reduce lower back pain (retrospective cohort study) .
3) May Ease Cerebral Palsy Symptoms
Methocarbamol had some beneficial effects on certain symptoms (spasticity diplegia) of cerebral palsy in 36 children (double-blind crossover trial). However, a meta-analysis of multiple papers rated this study as poor quality [15, 3].
4) May Alleviate Tetanus Symptoms
Methocarbamol was used to reduce symptoms in the treatment of tetanus, a bacterial (Clostridium tetani) infection that causes muscle tightening and spasms (11 patients) .
5) Can Slightly Lessen Spider Bite Symptoms
Methocarbamol was used to treat the effects of black widow spider bites but it was much less effective than calcium gluconate (1 out of 10 patients had improved symptoms from methocarbamol compared to 6 out of 13 from calcium gluconate) .
6) May Reduce Hospital Stay Length
Methocarbamol given to patients with broken ribs was associated with a shorter hospital stay (retrospective cohort study of 592 patients) .
7) Methocarbamol and Alcoholism
Methocarbamol (2-6 g/day) did not have any beneficial effects when used to treat symptoms of alcohol withdrawal, such as tremors and anorexia in with 113 alcoholics (double-blind randomized controlled trial) .
8) Methocarbamol and Poisonings
Methocarbamol and diazepam were used to treat convulsions and muscle spasms in a Bengal tiger that had been poisoned with a pesticide (toxaphene) .
Methocarbamol Is Not For Opioid Withdrawal
Although some anecdotal evidence has suggested methocarbamol is helpful for opioid withdrawal, there are no data to support this use.
Negative Effects of Methocarbamol
1) Side Effects
- Blurred or double vision
- Flushing (warmth, redness, or tingly feeling in the skin)
- A Headache
- Itching or rash
- Loss of balance or coordination
- Memory problems
- Mild weakness
- Sleep issues (insomnia)
- Upset stomach
2) Can Give a False Positive Test Result for Cancer
In a case report, methocarbamol give a false positive in a urine test (vanillylmandelic acid excretion test) for a type of adrenal cancer (pheochromocytoma). This urine marker is not used commonly anymore, though, as more sensitive and accurate urine tests are available (total urinary normetanephrine, platelet norepinephrine) [23, 24].
It can also give a false positive in a urine test (5-hydroxyindoleacetic acid excretion test) for a syndrome associated with carcinoid tumors (a malignant-carcinoid syndrome in intestinal and neuroendocrine tumors) [25, 26].
3) Has the Potential to Be Abused
4) Can Increase Risk of Injury in the Elderly
Methocarbamol and other muscle relaxants are not normally prescribed to the elderly because of an increased risk of falls and injury .
5) Can Cause Severe Stomach Issues
6) May Cause Inflammation
A 42-year-old woman experienced inflammation of blood vessels in the skin and severe stomach pain after a methocarbamol injection .
- Alcohol – can suppress breathing and even lead to death
- Appetite suppressants (and other stimulants) – methocarbamol can increase the effects of stimulants
- Barbiturates (sedative) – can suppress breathing and lead to death
- Benzodiazepines (sedative/anti-anxiety/anti-convulsant/hypnotic) – can suppress breathing and lead to death
- Codeine and related medications (opioid used to treat pain) – can suppress breathing to a fatal level
- Other muscle relaxants – can suppress breathing to a fatal level
- Drugs that treat anxiety, depression or other mental illnesses
- Yeast sucrase (used to treat a genetic disease, congenital sucrase-isomaltase deficiency (CSID)) – methocarbamol binds to and inactivates sucrase
Due to its short half-life (1.2 hours), methocarbamol is usually taken 2-4 times a day .
A normal oral dosage is 1,500 mg, 4 times a day (for the first 2-3 days), followed by 750 mg, 4 times a day .
Intravenous and Intramuscular
A normal intravenous/intramuscular dosage is 1,000 – 2,000 mg, 3 times a day .
Methocarbamol Combined With Other Drugs
The combination of methocarbamol with acetaminophen is commonly used to reduce pain from muscle spasms .
After a medical center switched from oral opiate pain medication to intravenous methocarbamol and intravenous acetaminophen for hip and knee replacement surgery, patients used fewer opiates to treat post-surgery pain. However, the author of the study received funding from the pharmaceutical company that produced the acetaminophen .
Ibuprofen is also commonly combined with methocarbamol to alleviate muscle spasm pain .
Methocarbamol reduced the dose of aspirin needed for pain relief (in mice) .
Methocarbamol (750 mg) and Naproxen (500 mg) used together to treat lower back pain was not better than naproxen alone in 240 patients (double-blind randomized controlled trial) .
Another study (single-blind randomized controlled trial) in 100 patients found that methocarbamol given before breast augmentation surgery alleviated pain but only within 6 hours after surgery (single-blind randomized controlled trial, 1,500 mg before surgery and 500 mg/every 6 hours with pain medication) .
Methocarbamol vs. Other Muscle Relaxants
Muscle relaxants are most commonly used for lower back pain relief, either in combination with anti-inflammatory pain medication (such as acetaminophen, ibuprofen, or aspirin) or when painkillers can’t be used .
Quite a few other drugs are used as muscle relaxants. However, unlike other drug classes (such as statins and beta-blockers), various muscle relaxants are not chemically similar. The following are the most commonly used muscle relaxants, which all have side effects such as nausea, dizziness, and drowsiness [3, 3, 1, 45, 46, 47, 48]:
- Baclofen (Lioresal) – approved to treat muscles contracting continuously (spasticity), blocks GABA receptors
- Carisoprodol (Soma) – has sedative effects
- Chlorzoxazone (Parafon Forte, Lorzone) – has sedative effects
- Cyclobenzaprine (Flexeril) – has sedative effects
- Dantrolene (Dantrium) – approved to treat spasticity, directly inhibits contractions
- Metaxalone (Skelaxin) – relatively strong muscle relaxant
- Orphenadrine (Norflex) – usually used to treat Parkinson’s Disease
- Tizanidine (Zanaflex) – has sedative effects, approved to treat spasticity
The most extensively researched muscle relaxant is cyclobenzaprine, which is similar to methocarbamol in efficacy and percentage of people who stopped use from unintended adverse effects. There are very few studies that directly compare methocarbamol to the other muscle relaxants [1, 3, 6].
Natural and Herbal Alternatives to Methocarbamol
Natural Substances That Reduce Muscle Spasms
Marijuana contains many medically beneficial compounds such as tetrahydrocannabinol (THC) and cannabidiol (CBD). Both THC and CBD can alleviate pain and muscle spasms. THC can also reduce nausea and vomiting due to chemotherapy treatment. Patients prefer marijuana and drugs containing cannabinoid compounds because of their safety and very few side effects .
CBD oil can also be used topically to treat pain and CBD patches are being developed .
A cannabis-based medication – cannabis extract containing THC and CBD – helped relieve the symptom of continuous muscle contraction (spasticity) in 189 patients with multiple sclerosis (double-blind randomized controlled trial) and reduced the frequency of spasms in another study in 57 patients (double-blind randomized controlled trial) [51, 52].
Cannabis extract improved a variety of symptoms such as pain, muscle spasms, and impaired bladder control in 24 patients with multiple sclerosis, spinal cord injury, nerve damage, or limb amputation from nerve tumors (neurofibromatosis) (double-blind randomized controlled trial) .
In a case study, a strain of medical marijuana (trainwreck) immediately eased muscle spasms caused by a cancer medication (Vismodegib) in a 58-year-old woman (3-4 marijuana joints/day, containing 18.6% THC, 0.0% CBD, and 0.0% cannabinol). The pharmaceutical muscle relaxants, baclofen, and cyclobenzaprine provided no relief .
Although a meta-analysis indicated more research is needed, 2,000 mg magnesium sulfate, a pharmaceutical preparation of magnesium, immediately relieved painful spasms in a 25-year-old paraplegic [55, 56].
In a prospective clinical study of 33 people, magnesium sulfate reduced muscle stiffness and spasms in those with mild tetanus. Those with severe tetanus required additional medication .
Magnesium controlled muscle spasms of 38 of 40 people with a tetanus infection .
Magnesium sulfate also successfully treated tetanus symptoms in a dog, when other muscle relaxants (benzodiazepine, methocarbamol, and barbiturate) were not effective enough in controlling muscle spasms .
Natural Substances That Reduce Muscle Pain
Serrapeptase (also known as serratiopeptidase, serralysin, serratiapeptidase, or serrapeptidase) is a protein that breaks down other proteins (protease), isolated from silkworm gut bacteria. It can relieve pain and inflammation [60, 61, 62, 63, 63, 64].
Normally, post-workout muscle pain is treated with pharmaceutical painkillers, mostly commonly non-steroidal anti-inflammatory drugs (NSAIDs such as aspirin and ibuprofen). Curcumin is thought to act in a similar way and could be used as a natural alternative .
Curcumin (2,500 mg) taken twice a day reduced the muscle pain experienced post-workout by 17 men (double-blind randomized controlled trial). This effect was likely due to its anti-inflammatory properties .
However, in a study with 28 men, taking 400 mg/day curcumin did not reduce muscle soreness post-workout .
Boswellia serrata (also known as Indian frankincense) extract in the form of a daily supplement (Casperome) provided 52 healthy athletes with pain relief for different types of joint and muscle pain .
Boswellia sacra extract had similar pain-relieving effects of aspirin in mice .
4) Cat’s Claw
It also helped relieve pain in mice .
5) Tart Cherry
Tart cherry (Prunus cerasus) helps with muscle recovery after strenuous exercise. Long distance runners had reduced post-run pain after consuming tart cherry juice 7 days prior and during the run in 54 healthy runners (double-blind randomized controlled trial, 355 mL 2 times a day) [73, 74, 75].
Ginger (Zingiber officinale) has been used to treat pain and has similar properties to non-steroidal anti-inflammatory drugs (NSAIDs). However, while there is not much data (especially well-designed studies) about its effects on muscle pain, a few studies show ginger has a slight pain relief effects (especially at a dose of 2,000 mg taken for at least 5 days) [76, 77, 78, 79].
Ginger (500 mg of ginger rhizome powder) was as effective as ibuprofen (400 mg) in reducing pain and inflammation following oral surgery in 60 patients (double-blind randomized controlled trial) .
In two studies, a ginger supplement (2,000 and 4,000 mg) did not improve muscle soreness post-exercise (double-blind randomized controlled trial of 27 adults and placebo-controlled trial of 20 adults). But in two studies, ginger supplementation did offer benefits (2,000 mg) given before exercise (double-blind randomized controlled trial of 74 adults, placebo-controlled trial of 36 healthy females) [76, 81, 82, 83].
Methylsulfonylmethane (MSM) is a naturally occurring chemical compound. An MSM supplement (OptiMSM) mildly reduced post-exercise muscle and joint pain in 22 healthy adults (3,000 mg/day, double-blind randomized controlled trial) .
8) Vitamin D
A vitamin D deficiency (also known as rickets and hypovitaminosis D) is associated with muscle weakness and pain. Thus, vitamin D supplementation can reduce muscle pain and weakness in those with a deficiency [85, 86, 87].
The members of the Nepeta genus contain compounds (terpenoid-type compounds and phenolic constituents) that have a variety of helpful effects, mainly, pain relief .
A compound (kirmanoic acid) extracted from Nepeta clarkei had anti-inflammatory, pain relieving, and sedative effects in mice. Nepeta clarkei is a plant that belongs in the same genus that catnip (Nepeta cataria) does .
Citronellal is an essential oil (monoterpene) isolated from several species of lemongrass (Cymbopogon) that had pain-relieving effects in mice .
Another compound from lemongrass, citronellol (monoterpene alcohol) also had pain-relieving effects in mice .
11) B Vitamins
Chamomile refers to several different species of plants. The most commonly used species are Matricaria chamomilla, Chamomilla Recutita, and Chamaemelum nobile. The compounds found in these species can have sedative/calming effects, which might be helpful for people experiencing muscle pain .
Apigenin extracted from Matricaria recutita L. had slight sedative effects in mice (but no muscle relaxant or anti-convulsant effects) .
Although it didn’t have anti-anxiety, muscle relaxing, or anticonvulsant effects, apigenin (extracted from Matricaria chamomilla L.) reduced rat movement. It is possible chamomile can be used to produce a calming effect in humans .
Menthol is frequently used as a counterirritant, which provides a distracting sensation on the skin to detract from muscle aches and pain. Topical treatment of 3.5% menthol gel was better than ice in reducing muscle pain. A patch with 3% menthol and 10% methyl salicylate (another counterirritant) successfully treated people with mild to moderate muscle strain (randomized controlled trial with 208 adults) [99, 100].
Mentholated cream, especially with essential oxygen oil (oxygenated glycerol triesters) added, lowered pain levels (double-blind study with 66 adults). Essential oxygen oil is also a topical pain treatment [101, 102].
Capsaicin, a chemical compound found in chili peppers (plants in the genus Capsicum), is what causes the burning sensation when consuming peppers. Research suggests it can be used as a topical treatment for pain because it reduces sensitivity to pain. However, it can have some side effects due to its ability to irritate the skin (burning, pain, stinging, redness, itching, swelling, rashes, and dryness) [105, 106, 107].
4) Arnica and Brazilian Arnica
Arnica (Arnica montana), also known as mountain tobacco, and leopard’s bane, is a plant with pain relief properties. The literature on whether arnica can be used topically to relieve pain is mixed, which may be due to the different preparations of the plant. Herbal preparations are much stronger and have active ingredients, unlike the homeopathic version .
A gel containing arnica (50 g tincture/100 g gel) was as beneficial as ibuprofen (5% gel) when applied to the hands of arthritis patients (double-blind randomized controlled trial with 204 patients). Other studies came to a similar conclusion [112, 113, 114].
Another plant in the family (Asteraceae) that Arnica montana belongs to, Brazilian arnica (Solidago chilensis Meyen) has pain relief properties similar to arnica. A gel containing 5% Brazilian arnica was used to successfully reduce lower back pain (double-blind randomized controlled trial of 20 adults) .
Chamomile has many beneficial compounds, the most notable being apigen, which has pain relieving effects. A 0.233 mg/g apigen gel provided migraine relief (double-blind randomized controlled trial with 72 adults) .
6) Aromatherapy /Essential Oils
Acupressure combined with aromatherapy using oil containing a 2:1:1 ratio of rosemary, lavender, and peppermint essential oils was more effective in reducing shoulder pain than acupressure alone (randomized controlled trial with 30 patients with hemiplegic shoulder pain) .
Limitations and Caveats
Almost all of the studies that looked at methocarbamol efficacy were subjective (based on patients’ assessment of pain levels). Some of these studies lacked proper controls. There are very few studies that directly compare methocarbamol to other muscle relaxants. Methocarbamol is also frequently used with pain medication, so it can be difficult to measure its effect .
Those with an autoimmune disease, myasthenia gravis, most likely should avoid taking methocarbamol, as their response to muscle relaxants can be unpredictable. Drugs used to treat myasthenia gravis can also interact negatively with muscle relaxants [121, 122, 123].