Rifaximin SSD in Dementia Trial

Inclusion criteria

• Probable Alzheimer's Disease (AD) or Vascular Dementia (VaD) mild or moderate based on Clinical Dementia Rating Scale.
• Males and Females Age ≥ 65 years
• Community living with availability of caregiver to accompany participant to study visits and to participate in the study.
• Able to consent or legal guardian who can consent (with participant assent).
• Legally authorized representative (LAR) and caregiver for the study is the same individual.
• Fluency (both participant and caregiver) in written and spoken English to participate in study visits.

Exclusion criteria

• Dementia not due to AD or VaD
• Clinically significant agitation or aggression (requiring treatment with antipsychotic medication)
• Delusions and/or hallucinations
• Severe psychopathology including major depression
• Unstable, severe, or poorly controlled medical conditions evident from physical examination or clinical history
• Visual and/or hearing disorder that prevents completion of neuropsychologic evaluations.
• Diarrhea
• Hypersensitivity to rifaximin, components of rifaximin,
• and any rifamycin antimicrobial agent
• Antibiotic use in the prior 6 months
• Taking medications that interact with Rifaximin. P-glycoprotein (P-gp) inhibitor treatment is permitted as long as the use of P-gp inhibitors is discussed with the investigator.
• History of alcohol and/or drug abuse
• Participation in another investigational drug trial in the last 30 days