Rasagiline in Subjects With Amyotrophic Lateral Sclerosis (ALS)

Inclusion Criteria: 1. A clinical diagnosis of laboratory-supported probable, probable, or definite ALS, according to a modified El Escorial criteria, by the study investigator (Appendix IV). 2. 21 to 80 years of age inclusive. 3. VC greater or equal to 75% of predicted at screening and baseline. 4. Onset of weakness within 2 years prior to enrollment. 5. If patients are taking riluzole for ALS, they must be on a stable dose for at least thirty days prior to the baseline visit. 6. Women of childbearing age must be non-lactating and surgically sterile or using an effective method of birth control and have a negative pregnancy test. 7. Willing and able to give signed informed consent that has been approved by the Institutional Review Board (IRB). Exclusion criteria 1. Requirement for tracheotomy ventilation or non-invasive ventilation for \> 23 hours per day. 2. Patients on sympathomimetic agents. This includes pseudoephedrine, phenylephrine, phenylpropanolamine, and ephedrine. 3. Patients on analgesics with serotoninergic properties such as meperidine, tramadol, methadone and propoxyphene, flexeril. 4. Patients on fluoxetine or fluvoxamine. 5. Patients taking amitriptyline \> 50 mg/d, trazodone and sertraline \> 100 mg/d, citalopram \> 20 mg/d or paroxetine \> 30 mg/d. 6. Diagnosis of other neurodegenerative diseases (Parkinson disease, Alzheimer disease, etc). 7. Clinically significant history of unstable medical illness (unstable angina, advanced cancer, etc) over the last 30 days. 8. Has a diaphragm pacing device or plan on obtaining a diaphragm pacing device during the course of the study. 9. History of renal disease. 10. History of liver disease. 11. Current pregnancy or lactation. 12. Limited mental capacity such that the patient cannot provide written informed consent or comply with evaluation procedures. 13. History of recent alcohol or drug abuse or noncompliance with treatment or other experimental protocols. 14. Vital Capacity (VC) \< 75% of predicted. 15. Receipt of any investigational drug within the past 30 days. 16. Women with the potential to become pregnant who are not practicing effective birth control. 17. Poorly controlled hypertensive subjects or resting systolic blood pressure (SBP) \> 160 mmHg and/or diastolic (DBP) \> 95 mmHg. 18. Use of BiPAP at screening.