What is Muscle Relaxants and What is the Main Side Effect of Muscle Relaxants ?

Muscle relaxers or muscle relaxants are medications used to treat acute muscle pain and discomfort caused by muscle spasms. Muscle spasms are involuntary contractions that cause excessive strain in muscles and are often associated with conditions such as lower back pain and neck pain.

Medications used as muscle relaxers can differ in their chemical structures and the way they work in the brain. In general, muscle relaxers act as central nervous system depressants and cause a sedative effect or prevent your nerves from sending pain signals to your brain. The onset of action is rapid and effects typically last from 4-6 hours.

Muscle Relaxants for Muscle Spasms

Muscle spasms are painful and may restrict mobility, which can limit your ability to perform even basic activities. Painful, tight muscles can also interfere with getting a good night’s sleep.

Muscle relaxants may help reduce pain, and improve movement and range of motion, but your doctor will likely recommend that you first try acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID). In some cases, these over-the-counter medications will be enough to help alleviate your pain.

If your muscle pain persists, your doctor may prescribe a muscle relaxant in addition to your pain medication. Below are common muscle relaxants (the generic names are listed first, with a brand name example in parentheses):

  • Baclofen (Lioresal)
  • Carisoprodol (Soma)
  • Cyclobenzaprine (Amrix)
  • Metaxalone (Skelaxin)
  • Methocarbamol (Robaxin)

When You Might Need a Muscle Relaxer

Your doctor might first suggest you try an over-the-counter medicine like acetaminophen (Tylenol) or ibuprofen (Advil) to treat your pain. But if those don’t work, or you can’t take them because you have another issue like liver problems or ulcers, you may need to try a muscle relaxant.

Muscle relaxants are ideally prescribed for acute rather than chronic pain. They may be an option if pain is preventing you from getting enough sleep. Because muscle relaxants cause drowsiness, they can help you get rest when you take them at night.

Some of the common side effects of muscle relaxers include:

  • Drowsiness
  • Dizziness
  • Agitation
  • Irritability
  • Headache
  • Nervousness
  • Dry mouth
  • Decreased blood pressure

The most commonly prescribed muscle relaxers are carisoprodol (Soma) and cyclobenzaprine (Flexeril). According to data from IMS Health, there were 4.2 million prescriptions of Soma and 28.4 million prescriptions of Flexeril dispensed in the United States in 2017.

Muscle Relaxant List
Muscle Relaxant List

What Are Side Effects of Flexeril?

Common side effects of Flexeril include:

  • dry mouth or throat
  • headache
  • blurred vision
  • drowsiness
  • dizziness
  • fatigue
  • loss of appetite
  • stomach pain
  • nausea
  • diarrhea
  • constipation
  • gas, or
  • muscle weakness.

Dosage for Flexeril –  For most patients, the recommended dose of Flexeril is 5 mg three times a day.

You shouldn’t drink alcohol while taking muscle relaxants. These medications make it hard to think and function normally, even if you take a low dose, so combining them with alcohol can increase your risk of an accident.

You also shouldn’t drive or operate heavy machinery while taking muscle relaxants. Some muscle relaxers start working within 30 minutes of taking them, and the effects can last anywhere from 4 to 6 hours

Muscle Relaxant Abuse

Muscle relaxers have a potential for abuse and addiction. Prolonged use can lead to increased tolerance and physical dependence, especially with Soma.3 For this reason, muscle relaxers are intended as a short-term treatment not to be prescribed for more than 2-3 weeks.

Unfortunately, many individuals take muscle relaxers alone or in combination with other illicit drugs for nonmedical reasons, such as to produce or enhance feelings of euphoria and dissociation. According to the Drug Enforcement Administration, Soma is one of the most commonly diverted drugs in the United States.2 Evidence also indicates prevalent misuse of Flexeril. In 2010 there were over 12,000 emergency room visits associated with Flexeril, and in 2016 over 10,000 calls to the Poison Control Centers had involved Flexeril.1

Muscle relaxer abuse can lead to serious dangers such as an increased risk of overdose, which can result in:

  • stupor
  • hallucinations
  • seizures
  • shock
  • respiratory depression
  • cardiac arrest
  • coma
  • death

Alcohol and Muscle Relaxers

Like muscle relaxers, alcohol also depresses the central nervous system. When alcohol is consumed with muscle relaxers the side effects are exacerbated. This can be very dangerous, leading to symptoms like:

  • Blurred vision
  • Urine retention
  • Extreme dizziness
  • Extreme drowsiness
  • Low blood pressure
  • Fainting
  • Memory problems
  • Liver damage
  • Increased risk of overdose

It is recommended to not drive or operate heavy machinery when under the influence of muscle relaxers. It is especially important to avoid drinking, as combining muscle relaxers with alcohol greatly increases your risk of an accident.

Withdrawal and Treatment

Regular use of muscle relaxers causes the brain to become used to its effects. If you attempt to suddenly stop using muscle relaxers you may experience withdrawal symptoms. Depending on the specific drug and how long you have been using it, there are various treatment options available to help you overcome your addiction.

For many people, Flexeril withdrawal causes mild symptoms such as nausea, headache, drowsiness, malaise, and discomfort. Symptoms tend to peak about 2-4 days after you last took the Flexeril, although in some people withdrawal symptoms may last for up to 1-2 weeks. For many people Flexeril detox can be done at home. However, if Flexeril addiction is accompanied by alcohol or opioid abuse the withdrawal symptoms from these other substances can be severe. In these situations, it may be best to undergo professional medical detox.

Soma withdrawal is usually more severe and can include symptoms like hallucinations and seizures. For your safety and comfort, it is often best to find an inpatient treatment program that includes a detox program to manage withdrawal symptoms. After detox patients can transition into the actual treatment phase of the program. Some people may not require a supervised detox program and will be able to undergo treatment on an outpatient basis.

Most inpatient and outpatient rehab programs include cognitive behavioral therapy that will help you learn the coping skills needed for long-term recovery.

Which Muscle Relaxants Are Best for Neck and Back Pain?

Stiffness and soreness in your neck and back can be difficult to deal with, especially when sleeping. Maybe you have a new injury, or you’ve aggravated an old one. Either way, if you feel this kind of pain at night, you may not sleep well. And then you may have more pain when you wake up.

In some cases, muscle relaxants can help relieve this pain and get you through these tough days. They do exactly what their name says: relax muscles. Reducing muscle tightness may improve new (acute) neck and back pain, especially when used at night.

But you need a prescription for muscle relaxers. And the evidence is mixed regarding how well they workTreatment guidelines don’t even agree on whether they should be prescribed.

Over-the-counter (OTC) pain relievers work better for neck and back pain than muscle relaxants alone. Examples of these are acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil) and naproxen (Aleve). Plus, there are effective treatments that don’t involve any medication at all, like home exercises, physical therapy, and/or posture training. That said, some people may benefit from taking an NSAID and a muscle relaxer together, especially at night.

Muscle relaxers work in different ways. They act on the muscles, nerves, or central nervous system. There isn’t enough evidence to suggest one muscle relaxer is better than another. So let’s look at nine popular muscle relaxants, including how well they work and their side effects.

1. Methocarbamol

Methocarbamol (Robaxin) is a well-studied medication that treats back pain. Compared to other options, it’s inexpensive and less likely to make you sleepy (sedated).

Taken as needed, 1,500 mg every 6 to 8 hours is a cheap and well-tolerated option for people who have new neck and back pain. It’s less sedating than other options, like cyclobenzaprine and carisoprodol. However, it may be less effective. In one study, almost 20% of those taking it stopped because it wasn’t helping their pain go away.

2. Cyclobenzaprine

Cyclobenzaprine is a reasonable first choice because it’s a cheap generic. But it has more potential for side effects, like sedation. This limits how you can use it during the day. Cyclobenzaprine may also cause dry mouth, especially in older adults. If this is a concern, consider a better non-sedating option.

At the standard dose of 10 mg to 30 mg a day, cyclobenzaprine (formerly branded as Flexeril) will make you sleepy. If you use it during the day, you’ll want to break your 10 mg tab in half and take 5 mg to lessen the drowsiness. Interestingly, one study found that a lower dose (15 mg per day) worked just as well as a higher dose (30 mg per day). There may not be any benefit when you take it alongside an NSAID like naproxen.

3. Carisoprodol

Carisoprodol (Soma) is a Schedule 4 drug (similar to benzodiazepines Ativan, Valium, and Xanax). Because of this, it has the potential for misuse. For this reason, you should not use it if you have a history of substance use.

Many believe that carisoprodol should be phased out as a muscle relaxant in favor of much better options. If prescribed, you should only use it for short periods of 2 to 3 weeks. Scientists don’t know how effective it is when taken for longer periods. Carisoprodol may cause drowsiness and dizziness. People over age 65 should not use it.

4. Metaxalone

Taken as 800 mg tablets 3 to 4 times a day, metaxalone (Skelaxin) has the fewest reported side effects. It’s also the least likely of the muscle relaxants to make you sleepy. It may work better for chronic lower back pain that is flaring up, rather than for pain that is new.

Metaxalone is a generic alternative for the brand medication Skelaxin, but it still costs more than most others. Insurance companies often don’t cover it because there are cheaper alternatives. But it works as well as cyclobenzaprine and carisoprodol (more info on those above) with fewer side effects and less sedation. So, paying cash may be worth it.

5. Tizanidine

Tizanidine (Zanaflex) is often used for spasticity in people with multiple sclerosis or cerebral palsy. Spasticity is where the muscles contract continuously, which leads to tightness and stiffness. The FDA has not approved tizanidine to treat neck or back pain.

For multiple sclerosis or cerebral palsy, tizanidine tends to have fewer side effects than Baclofen. But either medication may not make much difference in new low back pain when compared with ibuprofen alone. Tizanidine is not a first choice for new neck or back muscle pain.

6. Baclofen

Similar to tizanidine, Baclofen (Gablofen, Lioresal) is primarily used for spasticity in people who have multiple sclerosis or spinal cord injuries. Up to 20% of people taking it have drowsiness.  It’s not a first choice: There are better options for neck and back muscle pain. The FDA has not approved baclofen to treat neck or back pain.

7. Oxazepam and diazepam

Benzodiazepine medications like oxazepam (Serax, Zaxopam) and diazepam (Valium) are anti-anxiety medications. They are sometimes prescribed as muscle relaxants. But these really aren’t recommended because they don’t work well, are sedating, and can be habit-forming.

Plus, the FDA has not approved benzodiazepines for neck or back pain. Avoid these medications for neck and back muscle pain. There are much better options.

8. Chlorzoxazone

Chlorzoxazone (Lorzone) is not well studied for new low back and neck pain in adults. It wasn’t found to be effective for pain after spine surgery. Chlorzoxazone has also been reported as a rare cause of acute liver toxicity. Don’t choose this medication until you’ve exhausted all other options.

9. Orphenadrine

For neck and back pain in adults, the first four medications on this list work better than orphenadrine (Norflex), so save this as another last resort in the event the others don’t work.

Do muscle relaxers make you sleepy?

Yes, they can make you sleepy. In fact, sedation is one of the most common side effects reported. Dizziness and drowsiness are also commonly reported. That’s why they usually have a warning on the label that instructs you to avoid certain things while taking them, such as driving, caring for children, and operating heavy machinery.

Muscle relaxers can also cause other side effects and interact with other medications. It’s important to let your healthcare provider know about your medical history and which medications and supplements you’re taking.