Muscle Relaxants
Tight, stiff muscles are common in fibromyalgia. They can feel uncomfortably tense, and you may notice hard nodules in your muscles that feel like rocks. Your muscles hurt to touch and radiate pain. This is especially true for those in your shoulders, neck and back because they seldom get a break unless you’re sleeping. Perhaps one of many possible muscle relaxants for fibromyalgia will ease your tension.
Medications to relax tight muscles fall into a variety of drug classes. While tizanidine, baclofen, and metaxalone are classified as muscle relaxants, others can help. Examples include cyclobenzaprine, a tricyclic antidepressant, along with a couple benzodiazepines (clonazepam and alprazolam).
Despite your desire to find a medication that can ease muscle pain and stiffness, fibromyalgia patients are often disappointed by muscle relaxants. This is because the more potent types of muscle relaxants are equally sedating, e.g., tizanidine, baclofen, and cyclobenzaprine.1 You don’t want to go through the day feeling hung over, so what can you do?
Three fibromyalgia specialists answer this question and offer their advice.
Robert Katz, M.D.
Muscle relaxants do help reduce tenderness and may relax patients or ease their anxiety. I tend to prescribe tizanidine and low dose cyclobenzaprine, and I use them quite often in the treatment of fibromyalgia. I don’t want my patients sedated, but want their muscles relaxed.
Typically, I start with very low doses, sometimes half a tablet of the lowest dose, and see how they respond. I like to try to give these medications during the daytime when patients have their greatest amount of pain and muscle tenderness. Muscle relaxants have a transient effect. This means that patients cannot take them at bedtime to reduce morning stiffness eight hours later. They must be on board when the patient has the most amount of pain.
I suspect that this class of medications somehow relaxes the central nervous system a bit and they also have a relaxing effect on the peripheral system (i.e., the muscles). It is somewhat like getting a massage. However, I have never been able to document how much these agents reduce muscle tenderness.
Dr. Katz is a rheumatologist, and researcher, affiliated with Rush University Medical Center in Chicago, IL.
Richard Podell, M.D.
Some patients find benzodiazepines, cyclobenzaprine or metaxalone useful for reducing muscle pain, stiffness, twitching, and spasms. Two muscle relaxants used in multiple sclerosis to treat muscle spasms are tizanidine and baclofen. These medications are sometimes helpful in fibromyalgia too. The major drawback for daytime use of these two drugs is sedation. The exception is metaxalone because this medication does not affect the central nervous system. It is a peripheral-acting muscle relaxer but may be less effective for fibromyalgia.
With regards to dosing, I typically begin with 25-50 percent of the usual standard starting dose. As a group, fibromyalgia patients are very sensitive to medication side effects, necessitating that one start low and build up slowly. Otherwise, the initial drug effects are likely to bowl a patient over.
As to why these medications work, we know so little about drug mechanisms that I’ve learned to be quite humble. Some treatments should help in theory but they don’t, and vice versa. More impressively, various drugs act one way in one person and the opposite in others. And this is not just the case for people with fibromyalgia. It is well-known that benzodiazepine/valium-type relaxants cause sedation and relieve anxiety in most people. However, these agents produce activation and increased anxiety in a small yet significant subset of patients.
Dr. Podell is a retired internist who was affiliated with UMDNJ-Robert Wood Johnson Medical School, NJ.
David McLain, M.D.
I use tizanidine to improve the sleep in people with fibromyalgia. Taken at bedtime, it’s sedating and decreases muscle tightness and stiffness. It lasts for about eight hours, so its hypnotic effect is normally worn off by morning.
One study in fibromyalgia patients showed tizanidine reduced central nervous system levels of substance P, a transmitter that signals pain. This muscle relaxant helps calm the sympathetic nervous system’s hyperactivity known to disrupt fibromyalgia sleep. In addition, it reduces racing thoughts.
I did a study using 2 to 12 mg of tizanidine in a group of fibromyalgia patients. The drug significantly reduced pain, daytime fatigue, and overall function. Common side effects include sedation (desired at night), reduced blood pressure, dizziness, and dry mouth/eyes.
Like most treatments for fibromyalgia, tizanidine is often used in combination with other medications prescribed in low doses. This tends to work better than using the drug by itself.
Dr. McLain is a rheumatologist in Shelby, AL, who has researched the use of tizanidine in fibromyalgia.
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For more information on fibromyalgia, see Symptoms, Medications and Nondrug Treatments.
Benefits & Side Effects
What are the odds that a muscle relaxant will reduce the uncomfortable tension in your body? A study examining muscle relaxants prescribed for fibromyalgia indicates they work best for relieving spasms, cramps, and neck/shoulder tightness.2 So, if you have any of these symptoms, taking a muscle relaxant is more likely to provide beneficial results.
What about side effects? Sedation and dizziness are common, but each muscle relaxant causes different side effects. Below are some potential issues.
Cyclobenzaprine causes dry cotton-ball mouth and dry eyes, urinary retention (edema and bloating), vivid dreams, irregular heartbeat, and weight gain. The undesirable side effects usually occur right away, but the benefits of the drug may take up to two weeks. Start at the lowest possible dose to minimize side effects. You may need to wait 1-2 weeks before increasing the dose. Aside from its use as a muscle relaxant, cyclobenzaprine is also prescribed to treat fibromyalgia pain.
Tizanidine reduces blood pressure. If you have low blood pressure or become lightheaded easily, this side effect could be a showstopper for you.
Baclofen may cause dizziness, nausea, and headache. This medication does not stay active in the body for long (only 4 hours). As a result, frequent doses are required, which can be a drawback. However, baclofen appears to have pain-relieving and anti-seizure qualities in addition to relaxing the muscles.
Clonazepam and alprazolam: Both are benzodiazepines and regulated by the Drug Enforcement Agency (DEA) as schedule IV medications. They can be habit-forming, potentially addictive, and may impair cognition. Alprazolam needs to be taken twice a day while clonazepam is taken once a day.
Metaxalone should not be taken with a long list of drugs (check with your doctor). It also may cause dizziness and stomach/GI upset. On the upside, it’s not so sedating to restrict daytime use.
References for Muscle Relaxants
1. See S, Ginzburg R. Am Fam Physician 78(3):365-70, 2002. Free Report
2. Oldfield BJ, et al. JAMA Network Open 7(9):e2434835, 2024. Free Report