RecruitingPhase 4Drug trialAntihypertensive Mechanisms of Minocycline in Resistant HypertensionThe goal of this clinical trial is to learn about the mechanisms by which minocycline effect blood pressure in individuals with treatment-resistant hypertension. The main questions it aims to answer are: * To what extent does minocycline lower blood pressure? * Are such blood pressure effects mediated through changes in gut microbiota, gut leakiness, systemic inflammation, neuroinflammation, or some combination of these? Participants will be randomly assigned to treatment with minocycline or placebo, treated daily for 3 months, to evaluate these questions.