This study aims to improve cognition and function in patients with Alzheimer's Disease (AD) by administering the oral antibiotic, Rifaximin. Rifaximin is a virtually non-absorbed antibiotic with the unique properties of lowering blood ammonia levels and altering gut microbiota. It is FDA approved for use in patients with hepatic encephalopathy. Rifaximin lowers blood ammonia by altering fecal flora by blocking bacterial RNA synthesis and also by increasing small bowel glutaminase. The Investigators hypothesize that rifaximin will improve cognition and function in AD patients by lowering blood ammonia and / or lowering circulatory pro-inflammatory cytokines secreted by harmful gut bacteria. The Investigators will enroll up to 10 subjects with probable middle stage Alzheimer's Disease. The subjects will be given rifaximin 550 mg orally twice daily for 3 months after evaluation to ensure they have no contraindications. Physician clinical and safety assessments, adverse events, as well as the ADAS-Cog-11 will be administered at baseline and at the 3 month endpoint and two months after stopping treatment (at month 5). Interim safety checks will occur via phone calls one week after baseline and then every 2 weeks till end point. Serum neuronal biomarkers, ammonia levels and pro-inflammatory and anti-inflammatory compounds will also be measured at those times. Bodily fluids (Stool samples) will also be collected. Because of a small risk of developing C. difficile up to 2 months following the last administration of rifaximin, the subjects will be followed for an additional 2 months after the 3 month treatment ends. Rifaximin is contraindicated in patients with hypersensitivity to rifaximin or rifamycin antimicrobials. Hypersensitivity reactions include exfoliative dermatitis, angioneurotic edema, and anaphylaxis. Clostridium difficile associated diarrhea is a risk whenever a patient is maintained chronically on antibiotics, with complications ranging from mild diarrhea to fatal colitis. Drug resistant bacteria can also result from long term use. There is increased systemic exposure to rifaximin in patients with severe hepatic impairment or in patients who are taking P-glycoprotein inhibitors concomitantly. Regarding use in geriatric patients, there were no reported overall differences in the safety of the drug when used in patients 65 years of age or over, when compared with younger subjects.
Age range
55 Years – 85 Years
Sex
ALL
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Number of Participants Experiencing Diarrhea Caused by Clostridium Difficile
Timeframe: 5 months
Change in ADAS Cog 11 Scores
Timeframe: At baseline and at 3 months