This article explains how muscle relaxers work, when they are used, and which types are available for people with osteoarthritis and other types of musculoskeletal pain. It also describes the possible risks and side effects of muscle relaxers, including when they should not be used.
How Muscle Relaxers Work
Muscle relaxers, also known as muscle relaxants, are a group of drugs with sedative properties. While people tend to think of sedatives as “sleeping pills,” the types used as muscle relaxers prevent nerve signals or pain impulses from reaching the brain. This action helps relieve muscle spasms and tension that contribute to musculoskeletal pain.
Different types of drugs are used as muscle relaxers. While they all have similar mechanisms of action (in that directly act on the central nervous system), they have different chemical structures and indications for use. Some have stronger sedative effects than others, while others are used to treat specific medical conditions (for example, injuries or diseases of the spinal cord).
Muscle relaxers can be broadly categorized as follows:
Benzodiazepines: These are central nervous system depressants typically prescribed to treat anxiety, insomnia, and seizures. The types used for pain are short-acting. Skeletal muscle relaxants: These are a group of drugs that block pain impulses to the brain (neuromuscular blockers) and/or relieve muscle spasms (spasmolytics).
When Muscle Relaxers Are Used
As a general rule, muscle relaxers are used for the short-term treatment of musculoskeletal pain. They can be used “on demand” when acute pain strikes but are generally not the drugs of choice for chronic musculoskeletal pain.
Furthermore, muscle relaxers are usually not used for the primary treatment of pain. More often, they are prescribed when other more conservative treatments, like over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs), fail to provide relief.
Muscle relaxers may be prescribed for people with the following conditions:
Osteoarthritis pain Lower back pain Neck pain Sprains or strains of muscles, ligaments, or tendons Tension headaches Fibromyalgia Spinal injuries Myofascial pain syndrome Temporomandibular joint (TMJ) dysfunction Multiple sclerosis
Some muscle relaxants cause greater drowsiness than others, especially certain benzodiazepines. This can be useful if the pain is interfering with your sleep.
List of Common Muscle Relaxers
Muscle relaxers are available by prescription. There are no OTC muscle relaxers. Many are prescribed in tablet, capsule, or liquid form, but there are also injectable forms used for rapid relief of acute pain.
Some of the more commonly prescribed muscle relaxants (by class) include:
Common side effects of muscle relaxants (by drug class) include:
Certain muscle relaxers pose a major risk of drug dependence. Among those known to be habit-forming are Amrix, Ativan, Restoril, Soma, and Valium. It is for this reason that these drugs are generally not prescribed for longer than four weeks when used for acute musculoskeletal pain.
The risk of dependence is increased when benzodiazepines are prescribed alongside opioid drugs like fentanyl.
Meanwhile, skeletal muscle relaxers like Dantrium, Flexeril, Lorzone, Robaxin, Skelaxin, Soma, and Zanaflex may need to be used with caution in people with preexisting liver or kidney disease. In some cases, the drugs may need to be avoided entirely.
Benzodiazepines are avoided during pregnancy.
Summary
Muscle relaxers are sometimes prescribed for people with osteoarthritis pain and other types of musculoskeletal pain. They are available by prescription only and intended for short-term use.
There are two broad categories of muscle relaxers (benzodiazepines and skeletal muscle relaxants), each of which acts on the nervous system in different ways. The drugs are usually not prescribed as the primary treatment of musculoskeletal pain but are rather reserved for when conservative treatments fail to provide relief.
A Word From Verywell
Muscle relaxers can be very effective for the treatment of severe muscle, joint, back, or neck pain. With that said, they are not intended for long-term use and should only be taken as prescribed.
If pain persists despite the appropriate use of muscle relaxants, speak with your healthcare provider. Other treatments may be available, like nerve blocks or radiofrequency ablation, that may not only be safer over the long term but provide more effective, sustained relief.
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