Nancy Holland, T. Jock Murray, and Stephen C. Reingold

A complex control of muscle movements normally allows some muscles to contract and some to relax when a movement is carried out. This control can inhibit certain muscles and contract others when there is disruption to nerves in the CNS, resulting in the simultaneous contraction of many muscles, both the ones that help (agonists) and those that oppose the movement (antagonists). This causes the "tone" to increase in all the muscles, the limb to feel tight, and the limb movements to be slower and less smooth. It is more work and more tiring to walk with legs that have spasticity.

Spasticity can be reduced by exercise and by normal use of the muscles. It is important to perform stretching exercises of the spastic, tight muscles to prevent contractures, a state in which the tight muscle shortens. Each muscle should be stretched fully and held for a minute.

A number of medications that are considered muscle relaxants do not work well in MS and can have side effects. The most effective medication for spasticity and the symptoms that it produces (spasms, cramps, pain, aching), is baclofen (Lioresal®), which can be taken in different ways depending on the symptoms, their severity, and the person's tolerance to the medication. Because some people have painful spasms only at night and minor spasticity in the daytime, a nightly dose may be all that is needed. Others need relief from spasticity all the time, and a schedule of four doses a day is developed.

Because all patients can reach a dosage level that seems too high, causing a general feeling of weakness and drowsiness, your doctor may start you with a very low dose, perhaps half a tablet (5 mg) twice a day, and slowly increase by adding a further half tablet every three days until symptoms are reasonably controlled. If symptoms are helped at a low dose, the dosage is held there. If a patient develops side effects when the dose is increased, these may be eliminated by skipping a dose and going back to the previous level. Baclofen is very helpful in reducing the spasms and pain sometimes associated with spasticity but is only somewhat helpful in improving function limited by spasticity.

Tizanidine (Zanaflex®) is an effective antispasticity agent that has effects similar to baclofen. It is especially effective for night spasms and is sometimes effective in reducing spasticity in patients who do not respond to other agents. Its use in combination with low doses of baclofen may produce an optimal antispasticity effect with fewer side effects. Tizanidine is less sedating than diazepam or baclofen.