Status_angiotensus
Refractory hypertension (RfHTN) is hypertension, a high blood pressure, that remains uncontrolled on maximal or near-maximal therapy, that includes the use of ≥5 antihypertensive agents of different classes.[1] Agents used include a long-acting thiazide-like diuretic (such as chlorthalidone) and spironolactone.[2] Refractory hypertension is typically associated with increased sympathetic nervous system activity.[2][3] The phenotype of refractory hypertension was first proposed in a retrospective analysis of patients referred to the University of Alabama at Birmingham Hypertension Clinic whose blood pressure could not be controlled on any antihypertensive regimen.[2][4]
Observational studies suggest that RfHTN is rare, affecting <5% of patients.[3]