Allopurinol Improves Heart Function in African Americans With Resistant Hypertension

African American adults in the United States have the highest prevalence rate of high blood pressure (hypertension) and heart failure in the world. African Americans with treatment resistant hypertension have higher levels of the enzyme - xanthine oxidase compared to Caucasians. This trial will test if administration of the xanthine oxidase inhibitor - Allopurinol (commonly used in the treatment of gout), given over a period of 8 weeks, will improve heart function, exercise ability and quality of life in African American Veterans with resistant hypertension.

Inclusion Criteria: In order to be eligible to participate in this study, an individual must meet all of the following criteria: 1. Veteran 2. African American 3. Resistant hypertension diagnosis (defined as blood pressure greater than 140/90 millimeters of mercury (mmHg) at 2 clinic visits despite the use of 3 antihypertensive medications at pharmacologically effective doses) 4. Locale - Birmingham, AL and surrounding areas Exclusion Criteria: 1. History of heart failure 2. Chronic kidney disease (estimated creatinine clearance \< 60 milliliters per minute (ml/min) 3. Chronic steroid therapy 4. Known coronary artery disease 5. Known causes of secondary hypertension 6. Already taking Allopurinol Magnetic Resonance Imaging Exclusion 1. Claustrophobia 2. Cardiac implantable electronic device (permanent pacemaker and/or intracardiac defibrillator) 3. Metal clips and/devices or other item that specifically prohibit safe cardiovascular magnetic resonance imaging (CMR)