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.
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.
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.
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.
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.