Potassium channel blockers are used to treat conditions like multiple sclerosis (MS) and Lambert-Eaton myasthenic syndrome (LEMS). These medications work by blocking potassium channels in nerve cells, which helps to improve nerve signaling and muscle strength. Potassium channel blockers come in oral tablets. Examples include dalfampridine ER (Ampyra) and amifampridine (Firdapse). You can choose the form that best fits your needs.