Anti-Diabetic Medications to Fight PD and LBD

Inclusion Criteria: * Parkinson's disease or Lewy Body Dementia (diagnosis confirmed by neurologist at Mayo Clinic) with stable neurological treatment in the past approximately three months. * Glucose intolerance or mild diabetes: The American Diabetes Association criteria for pre-diabetes/ glucose intolerance includes fasting glucose 100-125, random glucose 140-199, or hemoglobin A1C 5.7-6.4% and diabetes is \> 125 mg/dL, \> 200 mg/dL, and 6.5% or greater, respectively (40). It has been previously reported that 50-80% of individuals with Parkinson's disease have abnormal glucose tolerance (17), so this should not limit recruitment. Exclusion Criteria: * Use of insulin or other anti-diabetes medications other than metformin. * Contraindication to taking a DPP4 inhibitor or SGLT2 inhibitor including: allergy, history of angioedema, pancreatitis, active gallbladder disease, renal impairment with EGFR \< 45). * Bleeding disorder, use of anticoagulants, thrombocytopenia, or severe anemia. * Use of high dose steroids. * Current systemic chemotherapy. * Pregnancy or breastfeeding. * Recent (within 30 days) or recurrent (defined as more than one in the past 12 months) urinary tract infection or yeast infection. * Other contraindication that would make study participation unsafe or make study related data unable to be interpreted.