Phase IIb Study of Intranasal Glutathione in Parkinson's Disease

The study begins with a pre-screening telephone interview. During this conversation participants will be asked a series of questions that will help us identify whether they are eligible for participation in this study. The pre-screening interview process will take approximately 10 minutes and will include all screening criteria that does not require clinical or laboratory examination All routine research visits will take place at Bastyr University Campus (Kenmore, WA). Participants will be asked to schedule visits at approximately the same time of day each visit .If they are on medications, we would like them to take their medications as they normally would on the day of the visit. Participants will be randomly assigned to one of three different study groups- a low dose group, a high dose group, or a placebo group. Study participants will invited to volunteer for two magnetic resonance imagine (MRI) scans as part of this study, an optional part of study participation. For those who volunteer and qualify, MRIs will be performed at the University of Washington Radiology Department early in the morning. One scan will be taken at baseline before taking glutathione and the second upon completion of the study medication. There will be a separate consent form for those who participate in the imaging portion of this study. Among the participants who volunteer, the first 15 to qualify for an MRI scan will be scheduled according to MRI availability. If participants are enrolled in the study, they will be asked to keep a daily log of actual frequency of administration of study medication, if any, as well as any changes in their PD symptoms, any adverse events they might experience, and their general well-being. We are giving participants enough medication to last four weeks, until the date of their next appointment. The medication should be taken three times a day (morning, afternoon, and evening). Visit 1- Baseline: (Approximately 1 hour) * Urine sample * Venipuncture (blood draw, (40 mL / \~3 Tbsp) to assess blood antioxidant status.. * Clinical assessment of PD severity: Unified Parkinson's Disease Rating Scale (UPDRS), which involves assessing degree of tremor, ability to walk across the room, questions about ability to function independently (i.e. button your own shirt, feed yourself), and questions about mental health, including depression and intellectual impairment. * Participant will be taught how and when to administer the study medication and be given a 1-month supply. Visit 2- Week 4 follow-up: (Approximately 1 hour) * Urine sample * Venipuncture (blood draw, (40 mL / \~3 Tbsp) to assess blood antioxidant status.. * Clinical assessment of PD severity: Unified Parkinson's Disease Rating Scale (UPDRS) and Webster-Step Second test involve assessing degree of tremor, ability to walk across the room, questions about ability to function independently (i.e. button your own shirt, feed yourself), and questions about mental health, including depression and intellectual impairment. * Participant will be asked to return any unused study medication and applicator tips from the first month of the study and be given the next 1-month supply. * We will inquire about medication changes and collect medication use logs. Visit 3- Week 8 follow-up: (Approximately 1/2 hour) * Participant will be asked to return any unused study medication from the second month of the study and be given the next 1-month supply. * We will inquire about medication changes and collect medication use logs. Visit 4- Week 12 follow-up: (Approximately 1 hour) * Urine sample * Venipuncture (blood draw, (40 mL / \~3 Tbsp) to assess blood antioxidant status.. * Clinical assessment of PD severity: Unified Parkinson's Disease Rating Scale (UPDRS) to assess degree of tremor, ability to walk across the room, questions about ability to function independently (i.e. button your own shirt, feed yourself), and questions about mental health, including depression and intellectual impairment. * Participants will be asked to return any unused study medication from the third month of the study. * We will inquire about medication changes and collect medication use logs. Visit 5- Week 16 follow-up: (Approximately 1 hour) This visit is included to determine whether there are any lasting effects of the study medication one month following discontinuation of use. The visit will include: * Urine sample * Venipuncture (blood draw, (40 mL / \~3 Tbsp) to assess blood antioxidant status.. * Clinical assessment of PD severity: Unified Parkinson's Disease Rating Scale (UPDRS) which involves assessing degree of tremor, ability to walk across the room, questions about ability to function independently (i.e. button your own shirt, feed yourself), and questions about mental health, including depression and intellectual impairment. Overall, approximately 5 hours will be required for study participation. Blood draws will occur at most, but not all visits, and will not exceed 4 Tbsp per month.