What is muscle relaxant ?

If you have neck or back pain, or you’re dealing with some other condition that causes muscle spasms, your doctor might prescribe a muscle relaxer (or muscle relaxant) for you.
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 relaxant is a term usually used to refer to skeletal muscle relaxants (drugs), which act on the central nervous system (CNS) to relax muscles. These drugs are often prescribed to reduce pain and soreness associated with sprains, strains, or other types of muscle injury. Some examples of commonly prescribed skeletal muscle relaxant medications include carisoprodol (Soma), cyclobenzaprine (Flexeril), and metaxalone (Skelaxin), which are taken in tablet form.
Muscle relaxant drugs are only available by prescription in the U.S.
Other types of muscle relaxant drugs (neuromuscular blocking drugs) are sometimes used during the induction of general anesthesia or during insertion of an endotracheal (ET) tube.  These muscle relaxants are given intravenously (through the bloodstream) and act directly on the muscles. Examples of muscle relaxants used during surgical procedures include succinylcholine (Anectine, Sucostrin), atracurium (Tracrium), and pancuronium (Pavulon).
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.

When You Might Need a Muscle Relaxer

Your doctor might first suggest you try an over-the-counter medicine like acetaminophen (Tylenol) or ibuprofen (Advil) to treat your pain. But if those don’t work, or you can’t take them because you have another issue like liver problems or ulcers, you may need to try a muscle relaxant.

Muscle relaxants are ideally prescribed for acute rather than chronic pain. They may be an option if pain is preventing you from getting enough sleep. Because muscle relaxants cause drowsiness, they can help you get rest when you take them at night.

Side Effects

No matter what kind of muscle relaxer you take, you’ll experience one or more side effects. Some muscle relaxants, however, can have potentially serious side effects, like liver damage. Your doctor will work with you to find the medication that makes the most sense for your situation.

The most common side effects include:

      • Tiredness, drowsiness, or sedation effect
      • Fatigue or weakness
      • Dizziness
      • Dry mouth
      • Depression
      • Decreased blood pressure

You shouldn’t drink alcohol while taking muscle relaxants. These medications make it hard to think and function normally, even if you take a low dose, so combining them with alcohol can increase your risk of an accident.

You also shouldn’t drive or operate heavy machinery while taking muscle relaxants. Some muscle relaxers start working within 30 minutes of taking them, and the effects can last anywhere from 4 to 6 hours.

Addiction and Abuse

Muscle relaxants can be addictive for some people. Taking them without a prescription, or taking more than your doctor has recommended, can increase your chances of becoming addicted. So can using them over a long period of time.

Almost all cases of addiction and abuse are due to the drug carisoprodol (Soma), which is considered a schedule IV controlled substance. That’s because when the drug breaks down in your body, it produces a substance called meprobamate that acts like a tranquilizer. People who become addicted to carisoprodol sometimes abuse the drug because it makes them feel relaxed.

Other kinds of muscle relaxants may be addictive too. Cyclobenzaprine (Flexeril) has also been linked to misuse and abuse.

With prolonged use you can become physically dependent on some muscle relaxants. This means that without the medication, you can have withdrawl symptoms. You may have insomnia, vomiting or anxiety when you stop taking it.

Muscle Relaxant Prescription medications

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:

      • drowsiness
      • dizziness
      • headache
      • nervousness
      • 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
carisoprodol Soma tablet yes
carisoprodol/aspirin not available tablet yes
carisoprodol/aspirin/codeine not available tablet yes
chlorzoxazone Parafon Forte, Lorzone tablet yes
cyclobenzaprine Fexmid, Flexeril, Amrix tablet, extended-release capsule tablet only
metaxalone Skelaxin, Metaxall tablet yes
methocarbamol Robaxin tablet yes
orphenadrine Norflex extended-release tablet yes
tizanidine Zanaflex tablet, capsule yes

Antispastics

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
dantrolene Dantrium tablet yes
diazepam Valium oral suspension, tablet, injection yes
Warnings for prescription muscle relaxants

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:

  • alcohol
  • 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
Off-label medications for spasticity

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

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:

  • clonazepam (Klonopin)
  • lorazepam (Ativan)
  • alprazolam (Xanax)

Side effects of benzodiazepines can include drowsiness and problems with balance and memory. These drugs can also be habit forming.

Clonidine

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

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.

Over-the-counter options for muscle spasms

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:

  • ibuprofen (Advil, Motrin)
  • naproxen (Aleve)

Acetaminophen

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.

List of Common Muscle Relaxers

Muscle relaxers are used in addition to rest, physical therapy, and other measures to relieve discomfort. They are typically prescribed for short-term use to treat acute, painful musculoskeletal conditions. Muscle relaxers are occasionally prescribed for chronic pain (pain lasting longer than 3 months).

If you want to talk about muscle relaxant in our muscle relaxant forums.

Muscle relaxers are not a class of drugs—meaning they do not all have the same chemical structure or work the same way in the brain. Rather, the term muscle relaxer is used to describe a group of drugs that act as central nervous system depressants and have sedative and musculoskeletal relaxant properties.

Muscle relaxers may be prescribed to treat back pain:

      • Early in the course of back pain, on a short-term basis, to relieve pain associated with muscle spasms
      • When back pain causes insomnia (for their sedative effect)

Muscle relaxers are also prescribed for other conditions such as fibromyalgia, multiple sclerosis, and seizure disorders.

There are several types of muscle relaxer medications commonly used to treat back pain.

muscle relaxant
muscle relaxant

Common Muscle Relaxants

Muscle relaxers are usually prescribed to treat back pain in conjunction with rest and physical therapy. Common muscle relaxants include:

      • Baclofen. Muscle tightness and muscle spasms, including those related to spine injuries, may be eased with baclofen. The medication may be helpful in treating multiple sclerosis and stabbing nerve pain. It is available as a tablet and can be taken by children as young as 12 years old. Some common side effects could include nausea and vomiting, confusion, drowsiness, headache, or muscle weakness. Baclofen is rated C in the FDA’s A through X pregnancy safety ranking for medications, with A being the safest. The C category means that the medication should only be used if the benefits outweigh the risks.
      • Benzodiazepines. In addition to treating anxiety, alcohol withdrawal, and seizure disorders, such as epilepsy, benzodiazepines can also treat muscle spasms and skeletal pain. Benzodiazepines, such as diazepam (Valium), lorazepam (Ativan), and temazepam (Restoril), are typically only intended for short-term use. This limitation is due to their habit-forming potential and because they alter sleep cycles, leading to sleep difficulties once the drug is stopped. Benzodiazepines are sold as tablets, liquid, injections, and rectal gels. People who have myasthenia gravis, severe liver disease, serious breathing troubles, or some forms of glaucoma, should avoid taking diazepam. All benzodiazepines are rated D by the FDA for safety during pregnancy and are not recommended for women who are pregnant.
      • Carisoprodol (Soma). Carisoprodol relaxes muscles and eases pain and stiffness caused by acute bone and muscle problems, often caused by an injury. It is taken by mouth in tablet form and is also available in combination with aspirin or aspirin and codeine. Carisoprodol can be habit-forming, particularly if used in conjunction with alcohol or other drugs that have a sedative effect, including opioids (such as codeine). Common side effects include drowsiness, dizziness, and headache. People with a history of blood disorders, kidney or liver disease, and seizures may need to avoid Carisoprodol. It is rated C in the FDA’s pregnancy safety ranking for medications.
      • Chlorzoxazone (Lorzone). Chlorzoxazone is used for the relief of discomfort from acute, painful, musculoskeletal conditions. Chlorzoxazone is available as a tablet. Common side effects include drowsiness, dizziness, and nausea. Chlorzoxazone is not recommended for people with liver disease. It has not been rated by the FDA for safety during pregnancy.
      • Cyclobenzaprine (Amrix, Fexmid, FlexePax Kit, FusePaq Tabradol). Cyclobenzaprine eases stiffness and pain from muscle cramps, also called muscle spasms. It is available as a tablet and extended-release capsule. Cyclobenzaprine itself is not intended for long-term use (more than 2 to 3 weeks). Common side effects include blurred vision, dizziness or drowsiness, and dry mouth. It is not advised for those with an overactive thyroid, heart problems, or liver disease. Cyclobenzaprine is rated B by the FDA for safety during pregnancy, making it the safest muscle relaxant to use while pregnant.
      • Dantrolene (Dantrium). Dantrolene helps control chronic spasticity related to spinal injuries. It is also used for conditions such as stroke, multiple sclerosis, and cerebral palsy. Dantrolene is taken as a capsule or intravenous powder for injection. Drowsiness and sensitivity to light are common side effects. It can cause severe liver problems, and should not be taken by people with active liver disease. The FDA has given dantrolene a C rating for safety in pregnancy.
      • Metaxalone (Skelaxin, Metaxall, and Metaxall CP, Lorvatus PharmaPak). Metaxalone targets pain and muscle spasms from sprains, strains, and muscle injuries. It is available as a tablet or injection. Common side effects include drowsiness, dizziness, nausea, and vomiting. Metaxalone is generally not recommended for people with a known tendency to become anemic, and who have kidney or liver disease. Metaxalone may affect blood sugar tests for people with diabetes. The FDA has not rated metaxalone for safety during pregnancy.
      • Methocarbamol (Robaxin, Robaxin-750). Methocarbamol eases acute muscle and bone pain. It can be taken as a tablet or by injection. Common side effects include dizziness, headache, nausea, flushing, and blurred vision. Methocarbamol is generally not recommended to people with renal disease or failure, or a history of allergic reaction to the medication. The FDA has given methocarbamol a C rating for safety during pregnancy.
      • Orphenadrine. Orphenadrine is a medication used to relieve pain and stiffness caused by muscle injuries. It is available as an extended-release tablet. Common side effects include dry mouth, lightheadedness, difficult urination, heartburn, nausea and vomiting. It is generally not recommended to people with previous sensitivities to the ingredients, myasthenia gravis, those with glaucoma or certain types of ulcers. The FDA has given orphenadrine a C rating for safety during pregnancy.
      • Tizanidine (Comfort Pac with Tizanidine, Zanaflex). Tizanidine is used to treat muscle spasms caused by spinal cord injuries and other conditions such as multiple sclerosis. Tizanidine is available in tablet and capsule form and absorbs differently depending on whether it is taken on an empty stomach or with food. Common side effects include dry mouth, dizziness, constipation and tiredness. It should not be used by people taking fluvoxamine or ciprofloxacin or those who have liver disease. Tizanidine is rated in the C category for safety during pregnancy.

Sometimes the first muscle relaxers a doctor prescribes does not work as well as expected. It may be necessary to try an alternative if the initial prescription is not effective. Many drugs interact with muscle relaxers and a person should keep their health care provider informed of all prescription and non-prescription medications he or she is taking.

There is very little research regarding which muscle relaxers are most effective, so the choice of which medication—or whether to use one at all—is based on factors such as a person’s reaction to the medication and personal preferences, potential for abuse, possible drug interactions, and adverse side effects.

These medicines are usually taken by mouth (tablets, capsules or liquids). In general, your doctor will start off with a low dose and increase this gradually over a number of weeks. This is in order to help your body get used to these medicines. Injections into the back are always started in the hospital.

Cannabis extract is a spray for the mouth. It should be sprayed under the tongue or on to the inside of the cheek once or twice a day. Always change the area in your mouth where you spray, to prevent irritation of the mouth. Like other muscle relaxants you will normally start off with a low dose. The number of sprays used is normally increased over a number of days.

What are the possible side-effects?

As with most medicines, muscle relaxants have a number of possible side-effects. However, not everyone experiences them and they usually improve as your body adjusts to the new medicine. Most muscle relaxants cause muscle weakness as a side-effect. It is not possible in this leaflet to list all the possible side-effects for these medicines. However, see below for a list of the most common side-effects. For more detailed information, see the leaflet that comes with the medicine packet.

  • Baclofen – feeling sick, tiredness, drowsiness, problems with eyesight, weakness, dizziness, light-headedness, headache, dry mouth, breathing difficulties, aching muscles, sleeplessness or nightmares, feeling anxious or agitated, confusion, unsteadiness, increased need to pass urine, shakiness, increased sweating, and skin rash.
  • Dantrolene – feeling dizzy, sleepy, tired, or generally unwell, diarrhoea, feeling or being sick, tummy (abdominal) pain, headache, loss of appetite, rash, speech or sight difficulties, high temperature (fever), chills, difficulty in breathing, seizures. It may also cause inflammation of the lining around the heart (sometimes with fluid in the lungs). Liver toxicity is also a possible side-effect of dantrolene.
  • Diazepam – feeling sleepy, weak, or light-headed, forgetfulness, feeling confused or unsteady, feeling (or being) aggressive.
  • Methocarbamol – forgetfulness, allergic reactions, being anxious, blurred vision, a slow heart rate, being confused or dizzy, headache, heartburn, feeling or being sick, itching, rash, and low blood pressure.
  • Cannabis extract – feeling dizzy, depressed mood, diarrhoea or constipation, mouth ulcers or pain, feeling tired or sick, appetite changes. Hallucinations have also been reported.