Senicapoc in Alzheimer's Disease

Inclusion Criteria: * Age 55-85 * Fluent in either English or Spanish * Willing to be randomized to active drug (10 mg Senicapoc) vs. placebo (3:1 ratio) * Clinical Dementia Rating (CDR) global score of 1 or 0.5 * Education adjusted scores between 12-28 on the Montreal Cognitive Assessment (MoCA) at the Screening visit. * A consensus clinical diagnosis of either amnestic Mild Cognitive Impairment (MCI) or mild AD dementia. Diagnoses are made by a comprehensive case conference review for all participants in the ADRC longitudinal cohort and all CADC referrals, resulting in a consensus diagnosis made according to current research criteria. For patients referred from other clinics, the case will be reviewed by a study physician and neuropsychologist and only patients who satisfy criteria for probable AD (McKhann et al 1984) or amnestic MCI (Petersen et al 2004) will be eligible for enrollment. * Vision (with or without correction) of at least 20/50 for distant vision * All participants will need a study partner informant who has at least 6 hours of contact per week with the participant. The study partners are used to help answer questions on the subject's behalf, since many of them will be impaired and may need assistance with providing accurate information. The study partners are not asked to provide any opinions or judgements about the subjects. * For Females of childbearing potential: Must agree to practice a highly effective method of contraception throughout the study until…