13 Minutes

Edited & medically reviewed by THE BALANCE Team
Fact checked

When you’re feeling backache or muscle spasms or you have stiff muscles or pain of an injury, operation, or specific body posture, the physician will prescribe you a pain killer or muscle relaxer. These medications can be used for the short term or the long term depending upon the severity of the pain and patient characteristics. Some people might also develop a muscle relaxer addiction. 

Woman clutching her arm in pain.

Muscle relaxers are drugs prescribed to treat acute pain and discomfort in the muscles associated with the spasm of muscles. These medications are used along with or in place of other painkillers like opioids, barbiturates, or sedatives. This muscle pain can be of an accident origin or any stress during work. Muscle spasms are involuntary in nature that cause excessive stress in muscles. They are often linked with painful conditions such as pain in the lower back and neck.

Muscle relaxers are antispasmodics and anti-spastics drugs that are used to relieve the spasms in muscles and pain linked with a variety of conditions and ailments. These conditions include:

  • Cerebral palsy
  • Sprains
  • Arthritis
  • Bursitis
  • Rheumatoid spondylitis
  • Multiple sclerosis
  • Fibrositis
  • Strains
  • The urethral syndrome

Muscle relaxers or myorelaxants are pain-relieving medications. A doctor can prescribe you a muscle relaxer if you are suffering from pain in the neck and back of the body, or if you’re dealing with some other condition that causes muscle spasms in any part of the body. During a muscle spasm, muscles undergo involuntary contractions leading to twitching and cramping. Reasons for muscle spasms may vary, and can sometimes be very painful.

Drugs used as muscle relaxers have a different chemical composition as well as the mechanism of action in the brain. Most of the time, muscle relaxants act as depressants of the CNS that produce seduction effects. These medications prevent nerves from sending signals to the brain. The time of action of muscle relaxers is rapid lasting from 4-6 hours.

Read Also: The Side Effects of Alcohol and Vistaril Interactions

We can also say that muscle relaxers inhibit the transmission of spasmodic nerves across the neuromuscular junction, and decrease excitement levels in the muscle cells. By either mechanism, these drugs give relief from different spasms and ailments, but their side effects are unavoidable. 

Muscle relaxers help in relieving pain in the muscle. These drugs act on the central nervous system and have sedating effects. Due to this sedating effect, muscle relaxers when abused have a high potency of addiction. 

Related: Opioids and Painkillers Addiction

Muscle relaxers can be misused and cause dependence. They can be highly addictive because these drugs make users feel extremely calm and relaxed. Muscle relaxants are usually used for short-term treatment of pain and any misuse or even long-term use of them can lead to drug dependence and addiction. 

Every drug that tends to increase or decrease brain (CNS) function has the potential for addiction. Muscle relaxers have a sedating effect on the brain to relieve pain in muscles, so these medications can cause addiction.

Long-term use of muscle relaxers leads to increased dependence as well as tolerance. Both these conditions lead to drug addiction. Due to their high potency for abuse or addiction, these medications are usually prescribed for short-term treatment and should not be used for more than 2-3 weeks.  

Some elderly individuals with severe body pain and muscular spasms start taking muscle relaxers alone or in combination with other prescription drugs for some other reasons. These reasons may be to produce euphoria and dissociation or sometimes to relieve severe pain.

According to the (Drug Enforcement Agency), Abusers sometimes combine these drugs with CNS depressants to increase psychoactive effects or to induce euphoria and relaxation.

Common Signs of Muscle Relaxer Addiction and Abuse

If you are or a loved one is using muscle relaxants to relieve pain, you can confirm the drug abuse or addiction through several signs and symptoms. Here are a few common signs of addiction to muscle relaxers:

  • Needing larger or more frequent doses to get the same effect or euphoria
  • Continuously taking muscle relaxants after they’re no longer medically needed
  • Feeling tired or sick when effects of muscle relaxers wear off
  • Feeling impossible to stop using muscle relaxers
  • Loss of interest in regular hobbies and personal activities
  • Borrowing or stealing money to buy muscle relaxers from friends or drug dealers
  • Hiding muscle relaxer use from family and others
  • Major changes in sleeping habits and appetite
  • Taking muscle relaxants with other sedating drugs or alcohol
  • Faking injuries or back pain to obtain prescriptions for muscle relaxants
  • Going through a prescription and coming up with excuses for an early refill
  • Spending more time thinking about these drugs and the ways to maintain their supply

These signs can be mild to severe and depend on the type of drug, dose, and patient characteristics.


There are some side effects that indicate habitual use of muscle relaxers:

  • Depression
  • Constant sedation
  • Fatigue or weakness
  • Dizziness
  • Dry mouth
  • Drowsiness
  • Tiredness
  • Decreased blood pressure

Muscle relaxers when abused for a longer period or taken in a dose other than the prescribed one may produce various signs and symptoms of abuse and addiction.

Muscle relaxers when used for pain relief may produce physical, psychological, and behavioral effects. These effects vary depending upon the extent of the use of these medications. Because of side effects due to the use of muscle relaxers, individuals should not drive or operate machinery after taking them.

Short-Term Side Effect

Short-term abuse of muscle relaxer can cause severe side effects leading to impaired normal functioning, including:

  • Confusion
  • Nausea
  • Vomiting
  • Dizziness
  • Drowsiness or slurred speech

Long-term Side Effects of Abuse

Long-term abuse of these drugs also causes side effects which include:

  • Seizures
  • Paralysis
  • Insomnia
  • Hallucinations
  • Heart Failure
  • Irregular heartbeat
  • Tremors
  • An urge to get high or euphoria

Either muscle relaxers are abused for the short term or long-term, the effects may be produced. These effects vary from mild symptoms to life-threatening complications.

Common Side effects of Muscle Relaxers

  • Despite their potential to relieve pain, these medications still have some side effects. Some common side effects of muscle relaxers are listed below:
  • Dry mouth
  • Dizziness or Drowsiness
  • Irritability
  • Decreased blood pressure
  • Agitation
  • Nervousness
  • Headache

Can muscle relaxers cause depression?

Muscle relaxers have a mechanism to slow down brain function and relieve pain by stopping nerves to transfer pain signals to the brain. Skeletal muscle relaxants may slow down the functions of your central nervous system (CNS), leading to CNS depression. However, this depression is a result of less severe use of muscle relaxers and can be overcome by decreasing the use of causative agents (muscle relaxants) and by taking antidepressant drugs.

There are many types of muscle relaxers currently consumed in the market. These drugs have different mechanisms, potency, dosage, and brands. All types of muscle relaxers have some form of sedating properties. According to the consumer health website, muscle relaxers can be of the following types:

  • Cyclobenzaprine: The brand name of this drug is Flexeril. This drug is sedative in nature and its sedative properties prohibit the use of this drug during the day.
  • Methocarbamol:  The brand name of this drug is Robaxin. This drug is recommended by the physician to treat pain in the back. It has a less sedative effect than other options.
  • Carisoprodol: The brand name of this drug is Soma. It is a Schedule IV drug (having similarity with benzodiazepines Valium, Ativan, and Xanax). Soma can be abused. It causes drowsiness and dizziness. It is recommended for short-term use only due to its potency for addiction.
  • Metaxalone: The brand name of this drug is Skelaxin: This muscle relaxer has fewer side effects and the lowest sedation potential.
  • Chlorzoxazone: The brand name of this drug is Paraflex and is usually used with rest, physical therapy, or treatment.
  • Tizanidine: The brand name of this drug is Zanaflex and is often prescribed to patients having multiple sclerosis or cerebral palsy. 
  • Dantrolene: The brand name of this drug is Dantrium and is a postsynaptic muscle relaxer. It is used in muscle spasms linked with spinal cord injuries, multiple sclerosis, stroke, or cerebral palsy.

A Muscle relaxer abuse can lead to adverse side effects such as a greater risk of overdose or other complications. This abuse of muscle relaxers causes:

  • Hallucinations
  • Shock
  • Respiratory depression
  • Seizures
  • Cardiac arrest
  • Stupor
  • Coma
  • Death

These dangers can be fatal if the drug is overdosed or used regularly without a genuine medical reason.

Everything in the world of medicine when used unnecessarily or in excess than required produces its effects. These effects produced by a drug overdose may worsen the condition for which it was taken or make the user addicted to the drug. Muscle relaxers are the main cause of drug abuse or addiction in the patient. Causes of Muscle Relaxers overdose, amount of overdose, and effects of muscle relaxers overdose are listed below:

Causes of Muscle Relaxers Overdose

Numerous factors can urge you to take an overdose of muscle relaxers. These factors may include:

Advancing Age

With advancing age the metabolism of elderly people slows down and the drugs take more time to metabolize in their bodies. To get the same effect for muscle relaxation, elderly people are bound to take more doses of muscle relaxers. This overdose aggravates the chances of addiction.


The response of the same amount or dose of the drugs in women is entirely different than in men. Women are more sensitive to a particular drug than men. Studies show that more pills of muscle relaxers are required to produce the same sedative effect in men and in the same way more dose is required to consider it an overdose.

Genetic Factors

Genetic factors alongside other factors play a key role in determining the effects of dose on a specific condition or effect. Genetic factors vary from person to person, so there is a huge variation in the need for the drug to produce a specific amount of effect. Overdosing of muscle relaxers follows the same trend of genetic factors. More tablets are required to produce an effect on muscles.

Tolerance to the Muscle Relaxers

A sedative drug, when used regularly, builds tolerance in the body for that drug. The body will need more drugs to feel the same effect. This increased amount of drug causes an overdose which enhances the risk of addiction.

Combining Substances

When muscle relaxers are taken along with alcohol, painkillers, or other medication, the way these medications work changes along with the half-life of the drug changes as well. These combined substances affect the metabolism or even mechanism of the drug which urges the abuser to take an overdose of the muscle relaxers.

Co-Occurring Diseases

The metabolism of the muscle relaxers is also influenced by co-occurring physical or mental health disorders. These co-occurring conditions cause the users to take more doses to have the same sedative effect of the muscle relaxer. Due to the delayed metabolism, a user has to take more muscle relaxers to take a specific amount of effect.

Recreational Use

Some people also start using muscle relaxers to get high or euphoric, so they tend to take an overdose of the drug. This overdose is a major factor for muscle relaxers drug addiction.

Muscle Relaxers Overdose Amount

The dosage that is considered to be an overdose varies and it depends on the drug. The dosage of muscle relaxers that are usually considered to be an overdose is the ingestion of 3-5 times the dose prescribed by the physician. When a large amount of the drugs are taken within short intervals, this overdose can be fatal as well.

Common Signs of Muscle Relaxers Overdose

Overdose of muscle relaxers can produce different complications that can be of physical, psychological, and behavioral nature. Major symptoms of muscle relaxant overdose are listed below:

  • CNS depression
  • Respiratory depression
  • Seizures
  • Dizziness
  • Drowsiness
  • Hallucinations
  • Dilated pupils
  • Flushed skin
  • Coma
  • Hypotension
  • Rigidity
  • Decreased bowel sounds
  • Lethargy and confusion

Whether muscle relaxers are used to treat pain in the back or muscle-related pain in different parts of the body, the therapeutic effect of the drug depends on how long the drug or its metabolites remain inside the body. Many patients are curious about the length of time they can use a single dose of muscle relaxers. The half-life of a drug is a useful way to provide an idea of the time a drug remains in the body. There are several options that you can opt for when suffering from muscle pain Following are the names of prescription muscle relaxers with the average half-life of each drug inside the system

Meprobamate10 hours (Chronic use: up to 48 hours)
Cyclobenzaprine08 hours to 36 hours (Average: 18 hours)
Vecuronium70 minutes
Atracurium20 minutes
Metocurine50 minutes
Mivacurium10 minutes to 20 minutes
Rapacuronium20 minutes

Factors that Influence the Period of Muscle Relaxers Staying in the System?

When you think about how long muscle relaxers stay in the system, it is important to note that there is no specific time limit for a muscle relaxer to stay in the living system. Considering the half-life of a drug is a useful approach, but several other factors have a major impact on how long these drugs will stay in the system. The duration for which a muscle relaxer stays in your system is influenced by several factors. Some of the major factors include:

  • The half-life of the particular drug used
  • The type of muscle relaxer used
  • The dose of the drug used
  • The type of drug test used to detect the drug
  • Biological factors like age, weight, and overall health
  • The difference in how liver enzymes process drugs in men and women
  • Kidney function and liver function
  • The general health condition of a person
  • Drinking alcohol after muscle relaxers is also responsible for a prolonged stay in the system

Regular use of CNS drugs causes the brain to get used to its effects. Muscle relaxers follow the same trend. If you suddenly stop using muscle relaxers or slowly cut down their usage, you may experience withdrawal symptoms. These symptoms can be mild to moderate or even can be severe depending upon the drug and the nature of the person using it.

Muscles relaxant withdrawal symptoms

Due to the addiction to muscle relaxers, only those individuals experience withdrawal symptoms who do not have access to these drugs or suddenly stop using them.
Some withdrawal symptoms of muscle relaxants include:

  • Insomnia
  • Lethargy
  • Chills and sweating
  • Headache
  • Irritability
  • Muscle aches
  • Nausea

The severity of withdrawal symptoms depends on:

  • Dose of the drug
  • The type of muscle relaxer being taken
  • Whether it was taken in conjunction with other nervous system depressants or alcohol
  • For how long an individual had been using these drug

Withdrawal effects from muscle relaxers may last from a few days to a few weeks. Withdrawal can be sometimes painful and can be best treated at a treatment center by professionals.

Alcohol tends to depress the CNS like muscle relaxers. When patients consume alcohol along with muscle relaxers, it worsens the side effects. This can be dangerous leading to the following symptoms:

  • Fainting
  • Urine retention
  • Extreme dizziness
  • Extreme drowsiness
  • Low blood pressure
  • Blurred vision
  • Liver Damage
  • Greater risk of overdose
  • Memory problem

It is advised to avoid activities like driving or operating heavy machinery when you are under the influence of muscle relaxers. Muscle relaxers when combined with alcohol greatly increase the risks of an accident, so it is recommended to do not to drink before driving.



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