What are Muscle Relaxants?
A muscle relaxant is a class of medications that affect skeletal muscle function and decrease muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term “muscle relaxant” is used to refer to two major therapeutic groups: neuromuscular blockers and spasmolytics. Neuromuscular blockers act by interfering with transmission at the neuromuscular end plate and have no CNS activity.
Sedation and dizziness are the most commonly effects of muscle relaxant medications. Other commonly reported effects are blurred vision, clumsiness, and an unsteady gait. Therefore patients driving motor vehicles or operating heavy machinery should take these medications with extreme caution.
Less common side effects include stomach upset, nausea, constipation, diarrhea, hiccups, confusion, nervousness, restlessness, irritability, headache, and sleep problems.
More absolute contraindications exist with carisoprodol, cyclobenzaprine, and diazepam. Diazepam and carisoprodol are not recommended for older adults, pregnant women, or people who suffer depression or for those with a history of drug or alcohol addiction. Rare reactions have also been reported to a metabolite of carisoprodol, meprobamate.
There are a few rare side effects that have been reported with the use of muscle relaxants. Although rare, potentially fatal liver disease has been seen with dantrolene. Tizanidine appears to be associated with asymptomatic, reversible elevations of aminotransferases (liver enzyme), and both tizanidine and chlorzoxazone have been associated with rare cases of serious liver damage.
Because muscle relaxants work on the central nervous system, they may add to the effects of alcohol and other drugs that slow down the central nervous system. Therefore, patients taking muscle relaxants should not consume alcoholic beverages.
Conditions Treated with Muscle Relaxants
- Muscle spasms (increased muscle tone) can be caused by musculoskeletal conditions, such as back and neck pain or fibromyalgia, or neurological conditions associated with upper motor neuron lesions (brain and spinal cord), such as multiple sclerosis. Both underlying causes can result in localized tenderness, significant pain, limitation of movement, and disability. However, it is important to differentiate whether the pain is due to local injury or originating from the central nervous system (CNS).
Muscle relaxants could be effective depending on your specific pain condition. Talk to your doctor about your diagnosis to determine if this treatment is right for you.