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Muscle relaxers, or muscle relaxants, are medications used to treat muscle spasms or muscle spasticity.
Muscle spasms or cramps are sudden, involuntary contractions of a muscle or group of muscles. They can be caused by too much muscle strain and lead to pain. They’re associated with conditions such as lower back pain, neck pain, and fibromyalgia.
Muscle spasticity, on the other hand, is a continuous muscle spasm that causes stiffness, rigidity, or tightness that can interfere with normal walking, talking, or movement. Muscle spasticity is caused by injury to parts of the brain or spinal cord involved with movement. Conditions that can cause muscle spasticity include multiple sclerosis (MS), cerebral palsy, and amyotrophic lateral sclerosis (ALS).
Prescription drugs can help relieve the pain and discomfort from muscle spasms or spasticity. In addition, certain over-the-counter medications may be used to treat aches and pains associated with muscle spasms.
Prescription medications are divided into two groups: antispasmodics and antispastics. Antispasmodics are used to treat muscle spasms, and antispastics are used to treat muscle spasticity. Some antispasmodics, such as tizanidine, can be used to treat muscle spasticity. However, antispastics should not be used to treat muscle spasms.
Antispasmodics: Centrally acting skeletal muscle relaxants (SMRs)
Centrally acting SMRs are used in addition to rest and physical therapy to help relieve muscle spasms. They’re thought to work by causing a sedative effect or by preventing your nerves from sending pain signals to your brain.
You should only use these muscle relaxants for up to 2 or 3 weeks. The safety of longer-term use is not yet known.
While antispasmodics can be used to treat muscle spasms, they have not been shown to work better than nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen. In addition, they have more side effects than NSAIDs or acetaminophen.
The more common side effects of centrally acting SMRs include:
- reddish-purple or orange urine
- lowered blood pressure upon standing
You should talk to your doctor about the benefits and risks of these medications for the treatment of your muscle spasms.
List of centrally acting SMRs
|Generic name||Brand name||Form||Generic available|
|chlorzoxazone||Parafon Forte, Lorzone||tablet||yes|
|cyclobenzaprine||Fexmid, Flexeril, Amrix||tablet, extended-release capsule||tablet only|
Antispastics are used to treat muscle spasticity. They should not be used to treat muscle spasms. These drugs include:
Baclofen: Baclofen (Lioresal) is used to relieve spasticity caused by MS. It’s not fully understood how it works, but it seems to block nerve signals from the spinal cord that cause muscles to spasm. Side effects can include drowsiness, dizziness, weakness, and fatigue.
Dantrolene: Dantrolene (Dantrium) is used to treat muscle spasms caused by spinal cord injury, stroke, cerebral palsy, or MS. It works by acting directly on the skeletal muscle to relax the muscle spasm. Side effects can include drowsiness, dizziness, lightheadedness, and fatigue.
Diazepam: Diazepam (Valium) is used to relieve muscle spasms caused by inflammation, trauma, or muscle spasticity. It works by increasing the activity of a certain neurotransmitter to decrease the occurrence of muscle spasms. Diazepam is a sedative. Side effects can include drowsiness, fatigue, and muscle weakness.
List of antispastics
|Generic name||Brand name||Form||Generic available|
|baclofen||Lioresal, Gablofen, Lioresal||tablet, injection||yes|
|diazepam||Valium||oral suspension, tablet, injection||yes|
Muscle relaxants such as carisoprodol and diazepam can be habit forming. Be sure to take your medication exactly as prescribed by your doctor.
Muscle relaxants can also cause withdrawal symptoms, such as seizures or hallucinations (sensing things that aren’t real). Do not suddenly stop taking your medication, especially if you’ve been taking it for a long time.
Also, muscle relaxants depress your central nervous system (CNS), making it hard to pay attention or stay awake. While taking a muscle relaxant, avoid activities that require mental alertness or coordination, such as driving or using heavy machinery.
You should not take muscle relaxants with:
- CNS depressant drugs, such as opioids or psychotropics
- sleeping medications
- herbal supplements such as St. John’s wort
Talk to your doctor about how you can safely use muscle relaxants if you:
- are older than 65 years
- have a mental health problem or brain disorder
- have liver problems
Doctors can use certain medications to treat spasticity even when the drugs are not approved for that purpose by the U.S. Food and Drug Association (FDA). This is called off-label drug use. The following drugs are not actually muscle relaxants, but they can still help relieve symptoms of spasticity.
Benzodiazepines are sedatives that can help relax muscles. They work by increasing the effects of certain neurotransmitters, which are chemicals that relay messages between your brain cells.
Examples of benzodiazepines include:
Side effects of benzodiazepines can include drowsiness and problems with balance and memory. These drugs can also be habit forming.
Clonidine (Kapvay) is thought to work by preventing your nerves from sending pain signals to your brain or by causing a sedative effect.
Clonidine should not be used with other muscle relaxants. Taking it with similar drugs increases your risk of side effects. For instance, taking clonidine with tizanidine can cause very low blood pressure.
Clonidine is available in brand-name and generic versions.
Gabapentin (Neurontin) is an anticonvulsant drug typically used to relieve seizures. It’s not fully known how gabapentin works to relieve muscle spasticity. Gabapentin is available in brand-name and generic versions.
OTC treatment is recommended as first-line therapy for muscle spasms caused by conditions such as acute lower back pain or tension headache. This means you should try OTC treatments before prescription medications.
OTC treatment options include nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, or a combination of both. Your doctor or pharmacist can help you choose an OTC treatment.
Nonsteroidal anti-inflammatory drugs (NSAIDs)
NSAIDs work by blocking your body from making certain substances that cause inflammation and pain. NSAIDs are available in generic and brand-name versions. They’re typically sold over the counter. Stronger versions are available by prescription.
NSAIDs come as oral tablets, capsules, or suspensions. They also come as chewable tablets for children. Side effects of these drugs can include upset stomach and dizziness.
Examples of NSAIDs include:
Acetaminophen (Tylenol) is thought to work by blocking your body from making certain substances that cause pain. Acetaminophen is available in generic and brand-name versions. It comes as immediate-release and extended release oral tablets and capsules, orally disintegrating tablets, chewable tablets, and oral solutions.
The more common side effects of acetaminophen can include nausea and upset stomach.
You can often manage your muscle spasm or spasticity symptoms on your own, but in some cases, you may need medical advice or care. Be sure to call your doctor if you:
- have spasticity for the first time and don’t know the cause
- notice the spasticity is getting more severe, happening more often, or making tasks difficult
- have severe and frequent muscle spasms
- notice deformity of the parts of your body affected by muscle spasms
- have side effects from your muscle relaxant
- have a “frozen joint” due to contracture that decreases your range of motion or causes pressure sores
- have increasing discomfort or pain
It’s important to treat both spasticity and muscle spasms. Severe, long-term spasticity can lead to muscle contracture, which can decrease your range of motion or leave the affected joints permanently bent. And muscle spasms can not only be uncomfortable, they can also be a sign of an underlying medical problem.
Your muscle spasms or spasticity are likely treatable with rest, physical therapy, medications, or all of the above. Work with your doctor to put together a care plan that can ease your pain and get you moving comfortably again.