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What are muscle relaxants?

The term "muscle relaxant" is used to describe a wide variety of drugs that have been used to treat muscle pain or spasms. Muscle relaxants are prescription drugs.

How do muscle relaxants work?

Because of the wide variety of drugs that are sometimes considered to be muscle relaxants, it is not possible to describe the underlying mechanisms by which these drugs work (and in many cases, the mechanism is not known). Some of these drugs work to relax muscle by working directly on the muscle, whereas others work on the nerves supplying signals to the muscles.

What are the names of some muscle relaxants?

Generic nameBrand nameFDA approval (spasm-related)
abobotulinumtoxinADysportCervical dystonia, Muscle spasms
baclofenGablofen, LioresalGeneral spasticity
carisoprodolSoma, VanadomMuscle spasms
chlorzoxazoneLorzoneMuscle spasms
cyclobenzaprineAmrix, Flexeril, FexmidMuscle spasms
dantroleneDantriumGeneral spasticity
onabotulinumtoxinABotoxCervical dystonia, Muscle spasms
orphenadrineNorflexMuscle spasms
metaxaloneSkelaxinMuscle spasms
methocarbamolRobaxinMuscle spasms
rimabotulinumtoxinBMyblocCervical dystonia
tizanidineZanaflexGeneral spasticity

Note that several other medicines, notably diazepam (Valium), may also be used as a muscle relaxant and are not listed here.


Muscle relaxants can affect overall muscle tone and may be dangerous if muscle tone is needed for safe balance or movement. Taking these drugs with alcohol or opioids/narcotics can enhance these effects and this is particularly dangerous. Many muscle relaxants need to be tapered off slowly, rather than abruptly stopped. Other side effects include:

  • Drowsiness
  • Dry mouth
  • Fast heart beat
  • Gastrointestinal upset
  • Headache
  • Weakness.

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