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What is a Muscle Relaxer?

Karyn Maier
Karyn Maier
Karyn Maier
Karyn Maier

A muscle relaxer is a type of medicine usually prescribed to treat pain. Also known as skeletal muscle relaxants (SMRs), they are commonly referred to as simply pain pills. While they doesn’t contribute in any way to speed healing at the site of an injury, they do help relieve pain by decreasing the mobility and contraction of skeletal muscle.

There are two main classifications of muscle relaxers: neuromuscular blockers and spasmolytics. As the name of the former implies, it blocks nerve impulse activity to the muscle by either inhibiting acetylcholine synthesis or its action at receptor sites. In effect, this type causes temporary paralysis of the muscles. For this reason, it is sometimes given just prior to surgical procedures as an alternative or supplemental anesthesia.

Muscle relaxers are usually used to treat pain.
Muscle relaxers are usually used to treat pain.

A spasmolytic, on the other hand, is often referred to as a centrally-acting muscle relaxer due to its impact on the central nervous system. It targets muscles with the purpose of inhibiting spasms, in addition to alleviating pain. This is the most commonly prescribed type, and the very term "muscle relaxer" generally refers to a spasmolytic, although its definition has been extended to include neuromuscular blockers as well. Since some pain medications in this class do not exhibit central nervous system activity, however, a more accurate term for a spasmolytic is simply antispasmodic.

Muscle relaxers may have side effects, such as blurred vision and dizziness.
Muscle relaxers may have side effects, such as blurred vision and dizziness.

While many patients may respond positively to a muscle relaxer in terms of pain relief, variations between different drugs in this class make some medications less appropriate for certain injuries or conditions. For instance, baclofen is one type that has been found to be helpful in some neurological conditions, such as multiple sclerosis or cerebral palsy. This specific medication is not recommended for orthopedic disorders, however.

Blurred vision is among the side effects of muscle relaxers.
Blurred vision is among the side effects of muscle relaxers.

Taking a muscle relaxer for any condition does present certain risks. For one thing, one or more side effects may occur, such as blurred vision, dizziness or drowsiness. Some muscle relaxers may intensify the effects of other medications, further suppressing the central nervous system. In addition, there is the risk of dependency and abuse with long-term use of these pain medications.

Spasmolytics are the most commonly prescribed types of muscle relaxers.
Spasmolytics are the most commonly prescribed types of muscle relaxers.

There are also certain circumstances in which the use of some types of muscle relaxers should not be used. For example, metaxalone may cause false blood sugar readings in diabetics. Another medication, methocarbamol, may increase the risk of seizures in epileptics.

Since any type of muscle relaxer can carry risks to certain individuals, it is important that the patient discuss their medical condition and history at length with their healthcare provider. In addition, the patient should fully disclose all other medications currently being taken, including over-the-counter drugs and dietary supplements.

Karyn Maier
Karyn Maier

Contributing articles to WiseGEEK is just one of Karyn’s many professional endeavors. She is also a magazine writer and columnist, mainly for health-related publications, as well as the author of four books. Karyn lives in New York’s Catskill Mountain region and specializes in topics about green living and botanical medicine.

Learn more...
Karyn Maier
Karyn Maier

Contributing articles to WiseGEEK is just one of Karyn’s many professional endeavors. She is also a magazine writer and columnist, mainly for health-related publications, as well as the author of four books. Karyn lives in New York’s Catskill Mountain region and specializes in topics about green living and botanical medicine.

Learn more...

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    • Muscle relaxers are usually used to treat pain.
      By: takasu
      Muscle relaxers are usually used to treat pain.
    • Muscle relaxers may have side effects, such as blurred vision and dizziness.
      By: Burlingham
      Muscle relaxers may have side effects, such as blurred vision and dizziness.
    • Blurred vision is among the side effects of muscle relaxers.
      By: Africa Studio
      Blurred vision is among the side effects of muscle relaxers.
    • Spasmolytics are the most commonly prescribed types of muscle relaxers.
      By: 18percentgrey
      Spasmolytics are the most commonly prescribed types of muscle relaxers.