Study to Determine the Safety and Tolerability of Varenicline (Chantix®) in Treating Spinocerebellar Ataxia Type 3

Exclusion Criteria

• •1. Any unstable illness or concomitant medical condition that, in the investigator's opinion, precludes participation in this study. This includes other disorders that may affect gait or balance (stroke, arthritis, etc).
• •2. Pregnancy or lactation.
• •3. Concurrent participation in another clinical study.
• •4. Patients with a history of substance abuse.
• •5. Patients who currently smoke or have smoked within the past 12 months.
• •6. Presence of psychosis, bipolar disorder, untreated depression (BDI greater than or equal to 21), or history of suicide attempt.
• •7. Concurrent treatment with any MAOIs, Wellbutrin, or nicotine patches.
• •8. Dementia or other psychiatric illness that prevents the patient from giving informed consent (Mini Mental Status Exam score less than 24).
• •9. Legal incapacity or limited legal capacity.
• •10. Presence of severe renal disease (BUN 50% greater than normal or creatinine clearance \<60 mL/min) or hepatic disease.
• •11. Abnormal creatine kinase and/or platelet count in the past 6 months (as determined by lab reports obtained from primary care physicians or conducted at baseline).
• •12. Use of varenicline within the previous 30 days.
• •13. Ataxia derived from any other cause than genetically-confirmed SCA (including but not limited to alcoholism, head injury, Multiple Sclerosis, olivo-ponto-cerebellar atrophy or multiple system atrophy).