What are the side effects of antispasmodics?

In cases of spasticity, the use of antispasmodics must be weighed against their potential side effects. Before starting medication, the options offered by physical therapy and therapeutic exercise equipment should be explored. The challenge of antispasmodic therapy lies in identifying an appropriate dosage that reduces muscle tone without causing significant side effects.

The main side effects involve excessive muscle relaxation (an exaggerated “muscle relaxant” effect). This side effect is typical of ALS, as muscle weakness (paresis) and muscle wasting (myopathy) may also be present in addition to spasticity. Antispasmodics can (as a side effect) exacerbate ALS-related paresis (muscle weakness). In the worst-case scenario, antispasmodic therapy may successfully reduce muscle tone but at the same time accentuate muscle weakness. In this situation—after weighing both symptoms—antispasmodic therapy should be avoided.

Other adverse drug reactions associated with antispasmodics include nausea, lethargy, and fatigue. All of the side effects listed are common, but they do not occur in every case. These side effects will subside once the dose is reduced or the medication is discontinued entirely.