The purpose of the study is to evaluate the safety of sodium phenylbutyrate (NaPB) treatment in subjects with amyotrophic lateral sclerosis (ALS) and the ability to take this medication without major side effects.

Although it is known that nerve cells die in the brains and spinal cords of patients who have ALS, the cause of the cell death is unknown. There is evidence that this cell death may be caused by changes in DNA, the body's genetic material. Drugs such as sodium phenylbutyrate (NaPB) can increase the expression of genes, block how the motor nerve cells in ALS die, and may prove to be an effective therapy for ALS. NaPB has shown an improvement in survival in mice with conditions similar to ALS.

STUDY DESIGN:

All research participants will take sodium phenylbutyrate for a total of 20 weeks. The dose of medication will be increased every 2 to 4 weeks until a maximum, easily tolerated dose is achieved (study maximum is 21 g/day).

Inclusion Criteria:

• Diagnosed with ALS
• At least 18 years of age
• Women, who can become pregnant, must actively use effective birth control measures

Exclusion Criteria:

• Must not have any other neurological (nervous system) disease

Veterans only are eligible to participate at VA sites.