Can a common blood pressure pill protect the aging brain?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Diagnoses of Alzheimer's disease according to the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria. * Presence of a caregiver (friend or relative) who can assume responsibility for medication administrations, accompany the patient to all visits, and rate patient's condition. * Written informed consent form from both the patient (or surrogate) and caregiver. * A Mini-Mental State Examination score between 12 and 26 inclusive. * Prescription of donepezil (5-10mg/d), memantine (5-21mg/d), rivastigmine (3-6mg/d), galantamine or galantamine ER (8-16mg/d) for a minimum of 4 weeks prior to randomization. * Agreement not to take hydralazine. * Age 50 and over. Exclusion Criteria: * Non-Alzheimer primary dementia diagnosis (e.g., vascular dementia, Lewy body dementia, frontotemporal dementia, vitamin B-12 deficiency, hypothyroidism). * Diagnosis of any of the following conditions; major depression, delirium, alcohol or psychoactive substance abuse or dependency, schizophrenia, or delusional disorder as defined by Diagnostic and Statistical Manual (DSM)-5. * Diagnosis of systemic illnesses that would interfere with participation in the study or decrease the life expectancy to less than one year. * Currently being treated with hydralazine or a history of intolerance to oral therapy with hydralazine * Any intravenous treatment for heart failure, except IV furosemide (e.g. IV inotropes, pressors, nitrates or nesiritide) at the time of screening. * Systolic blood pressure \<100 mmHg, reversible etiology of acute heart failure such as myocarditis, acute myocardial infarction-over the past 4 weeks, arrhythmia and existence of pacing device (Acute myocardial infarction is defined as symptoms and major electrocardiogram (ECG) changes (i.e., ST segment elevations), and arrhythmia includes unstable heart rates above 120/min or below 50/min). * Existence of severe congenital heart disease (such as uncorrected tetralogy of fallot or transposition of the aorta) and severe aortic or mitral stenosis or severe rheumatic mitral regurgitation. * Concurrent use of phosphodiesterase type 5 (PDE5) inhibitors (e.g. Viagra, Etc.) * Cardiac revascularization within the last 3 months or likelihood of requiring coronary revascularization within the study period. eGFR (Glomerular Filtration Rate) \< 15ml/min/1.73m2, or on regular dialysis, or planned dialysis within the study period.