The protocol determines whether PRA is high, medium or low and then adjusts medications accordingly. The protocol assumes that 10% of PRA remains unblocked in patients taking an ACEI or ARB (1).
Low PRA (< 0.65 ng/ml/hr). Anti-V treatment is given until BP is controlled, or until PRA rises into the medium range without BP control at which point the patient is treated as having medium PRA. But, if an uncontrolled patient with low PRA is currently taking an anti-R drug type, the anti-R drug type is first stopped (if no compelling indications) and only restarted if its withdrawal causes BP to rise. BP may actually fall.
Medium or high PRA (> 0.65 ng/ml/hr): Anti-R treatment is given until BP is controlled, or until the PRA level is effectively blocked by an ACEI or ARB (PRA < 6.5 ng/ml/hr) or suppressed to < 0.65 ng/ml/hr at which point the patient is treated as an uncontrolled hypertensive with low PRA (except there is no need to test stopping the anti-R drug).
High PRA (> 4.5 ng/ml/hr). If an uncontrolled patient with high PRA is currently taking an anti-V type drug, the anti-V drug is stopped (if no compelling indication) and only restarted if its withdrawal causes BP to rise. BP may actually fall(2).