A Study of Ranolazine in ALS

Who May Qualify: - 18 years or older - Diagnosed with clinically definite, possible, probably, or lab-supported probable ALS per revised El Escorial criteria - Breathing assessment called forced vital capacity (FVC) greater than or equal to 50%. - Able to swallow pills at the start of the study and expected to for the length of the study. - If on ALS modifying medications must be on a stable dose at least 30 days. - Experiencing 4 or more cramps per week during a 2-week screening period. Who Should NOT Join This Trial: - Disease duration \< 5 years - Tracheostomy invasive ventilation, or noninvasive ventilation of more than 12 hours/day - Pregnant or lactating, adults unable to consent, and prisoners - Taking ranolazine or investigational drug or has received an investigational drug within 30 days (or 5 half-lives for drugs, whichever is longer) prior to screening - Medically uncontrolled comorbidities (heart, liver, kidney disease) - Baseline QTc interval prolongation \>450 ms for men/ \>470 ms for women, history of long QT syndrome, or medications which prolong the QT interval - Participation in an experimental drug trial less than 30 days before screening - Patients have to be on a stable dosage of any medications used to treat muscle cramps for ≥30 days or have been off these medications ≥30 days prior to randomization. Always talk to your doctor about whether this trial is right for you.