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What to know about muscle relaxants 

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Find out exactly how muscle relaxants work and the right time to take them. 

Mark Ray

By Mark Ray

Ever been on a run or at the gym and had a charley horse? Then you know exactly how painful muscle spasms can be. Muscle spasms are involuntary muscle contractions. They often happen in your back or legs.  

Muscle spasms can happen when you get hurt or overuse a muscle. Being dehydrated can cause them, too. So can low levels of potassium or calcium. 

Muscle relaxants (also called muscle relaxers) can reduce spasms. These medications act on your brain and spinal cord. They help your muscles relax and stop contracting, which eases the pain. (Recommended reading: When do muscle spasms signal a more serious problem?)  

Types of muscle relaxants 

There are 2 main kinds of muscle relaxants: antispasmodic and antispasticity medications. 

  • Antispasmodic medications affect how nerve signals are conducted through your brain and spine. They’re used for acute (short-term) pain. Examples include carisoprodol (Soma®, Vanadom), cyclobenzaprine (Fexmid®, EnovaRX-cyclobenzaprine, Active-cyclobenzaprine Kit, Amrix®, Cyclophene RapidPaq), metaxalone (Skelaxin®) and methocarbamol (Robaxin®). 
  • Antispasticity medications work on either the spinal cord or the muscles themselves. They’re used for long-lasting conditions such as multiple sclerosis and cerebral palsy. Examples include baclofen and dantrolene (Dantrium®). 

Antispasmodics are used for common problems such as low back pain. According to the Centers for Disease Control and Prevention, a quarter of U.S. adults have experienced low back pain within the past 3 months. 

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Muscle relaxants are a short-term pain fix 

Muscle relaxants work best for short-term pain caused by muscle spasms, according to Medhat Mikhael, MD. He’s the medical director of the non-operative program at the Spine Health Center at MemorialCare Orange Coast Medical Center in Fountain Valley, California.  

“Muscle relaxants are very helpful in the short term. They’re good for someone who has spasms because of an injury, trauma or after surgery,” he says.  

Many doctors have turned to muscle relaxants as auxiliaries to opioids to reduce the need for higher or long-term use of opioids. One study found that prescriptions for muscle relaxants doubled between 2005 and 2016. 

But Dr. Mikhael notes that they should be taken for only a few weeks at a time. “We tell our patients, ‘Our goal is to wean you off these,’” he says. After 3 weeks, the medications aren’t effective for relieving muscle spasms. 

Recommended reading: What to do when back spasms attack. 

What to know about the side effects of muscle relaxants 

“These medicines can sometimes make you sleepy and dizzy,” says Nilanjana Bose, MD. She’s a rheumatologist at Memorial Hermann Physician Network in Houston. Muscle relaxants “can cause difficulty with motor activities. They may also impair your driving. This depends on the amount and the type of drug,” Dr. Bose says. They can also cause dry mouth, constipation and nausea. 

If you’re 65 or older, dizziness and tiredness from muscle relaxants could lead to falls and fractures. Plus, Dr. Mikhael says, older patients metabolize medications more slowly than younger patients. So there’s always risk of medication accumulation and increased side effects. Your doctor should watch you closely for this.  

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You may also experience side effects if you take muscle relaxants with other antiseizure or antianxiety medications. More serious side effects include:  

  • Blurred vision 
  • Lightheadedness or fainting 
  • Confusion 
  • Urinary retention      

Talk to your doctor immediately if you have any of these symptoms. 

Muscle relaxants and addiction 

Muscle relaxants are safe and effective when used as directed. But using them for long periods increases the chances of addiction. So can taking more of the medication than your doctor ordered.  

When the medication breaks down in your body, it produces a substance called meprobamate. This acts as a sedative. People can crave that relaxed feeling even when they’re no longer using the medication for muscle spasms. 

When used for longer than a few weeks, you can become physically dependent on some muscle relaxants. If you stop taking the medication, you can have withdrawal symptoms. These can include insomnia, vomiting or anxiety. Talk to your doctor if you’ve been using muscle relaxants longer than ordered. Your doctor can help you wean off safely. 

Non-medication ways to help muscle spasms 

If a muscle relaxant isn’t right for you, other options are available that can lessen the pain. “There are natural agents that can be good muscle relaxants,” Dr. Mikhael says. These include: 

  • Lavender oil. It can ease muscle pain. 
  • Chamomile. This has flavonoids with anti-inflammatory properties. You can drink tea or rub essential oil into the muscle. 
  • Cherry juice. It can help fight inflammation and muscle pain. 
  • Cayenne pepper. This is a natural muscle relaxant, and it can be added to food or taken as capsules. 
  • Vitamin D. People who have regular spasms or muscle pain may lack vitamin D. You can take a supplement or find it in foods such as eggs, fish and fortified milk. 

Dr. Bose recommends getting lots of sleep, which may be the most natural way to relax muscles. Also, drink plenty of fluids. Try not to overwork the affected muscle. Using heat pads or ice packs on the muscle can make it feel better. 

Download Optum’s prescription coupon mobile app today to find discounts and compare costs at local pharmacies. 

Additional sources:
Acute back pain: Centers for Disease Control and Prevention 
Muscle relaxant prescriptions on the rise: University of Pennsylvania (2020). “Trends in Muscle Relaxant Prescribing”