Muscle relaxants are medications that are used to help relax the muscles and can be used to help reduce pain that comes from strains, sprains, cramp and muscular injuries. They can also help to combat general stress and can be used to aid sleep (and even to prevent sleepwalking). These muscle relaxants work by depressing the central nervous system and thereby preventing the signals from the brain and spine that cause the muscles to tense.

Muscle relaxers can fall into two categories – neuromuscular blockers and spasmolytics. The neuromuscular blockers work by blocking the transmission at the neuromuscular end plate, and are useful for intensive care and surgical procedures in order to cause paralysis. Meanwhile spasmolytics are ‘centrally-acting’ relaxants and these are the ones you will use to relieve pain and spasms and to reduce spasticity.

Here we will look at some of these muscle relaxants, how they each work, and which are the best ones for specific uses.

Note: You should not take muscle relaxants along with alcohol. The reason is that these relaxants are depressives, in that they depress the nervous system. As alcohol is also a depressive, this means that it can increase the effects of the muscle relaxants and thereby be potentially dangerous.


Flexeril is also sometimes known as cyclobenzaprine. There are some side effects however including dizziness, fatigue, dry mouth, impaired thinking, confusion and in some rare cases seizures and strokes. This should not be used by those with heart conditions or hyperthyroidism.


GABA works is a naturally occurring substance that acts as a serotonin re-uptake inhibitor (and so can be used as an antidepressant) as well as increasing the secretion of melatonin and growth hormone. It is often used as a sleeping aid, and due to its impact on growth hormone secretion it can also be used as a bodybuilding aid. Side effects though include drowsiness and nausea and possible permanent hormone changes.


Valium, AKA diazepam, is a benzodiazepine used to treat anxiety and insomnia due to its ability to relax the CNS. This works by binding to a subunit on the GABAa receptor site and this actually enhances the affect of GABA in the brain. They also cause an increase in chloride ion resulting in more chloride ions in the neuron. Unfortunately side effects include drooling, blurred, vision, vertigo, slurred speech, confusion, depression and low blood pressure.


Also known as metaxalone, skelaxin is a fairly strong relaxant that has few side effects compared to other relaxants. However it is not safe for those with kidney disease, liver disease or anemia. Interestingly the exact mechanism of action is not fully understood, but it causes generally high CNS depression.


Also called, soma, carisoprodol is a relaxant that blocks pain sensations from the nerves via the central nervous system. It is great for blocking the pain in sprains and spasms and can also be used as an antidepressant.


Also known as tizanidine, zanaflex – an a2 adrenergic agonist – has a particularly high number of side effects. These include low blood pressure, fever, low heart rate, urinary tract infection and slurred speech. In other circumstances it may also cause hypotension, high blood pressure, and can cause corneal and retinal damage, kidney toxicity and hallucinations.

1 Comment

  1. Great article

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