Optimal Timing of ACE Inhibitor and ARB Dosing: Morning versus Evening Administration in Hypertension Management

Hypertension affects 1.4 billion people globally. Blood pressure typically dips during sleep, following a circadian rhythm. There is ongoing debate about the best time to take RAAS inhibitors. If these drugs lose their effect while a patient sleeps, it may disrupt this natural dip, raising the risk of heart problems. The aim of this focused narrative review is to assess whether it is optimal for blood pressure control and reduction of cardiovascular events to take RAAS blockers (ACE inhibitors and ARBs) at night or during the day. Randomized controlled trials and chronotherapy studies evaluating the effect of dosage time on blood pressure and cardiovascular outcomes are among the assessed evidence. Particularly when evaluated using ambulatory blood pressure monitoring, smaller RAAS-specific trials show better nighttime blood pressure management and restoration of nocturnal dipping with evening dosage. Larger pragmatic trials and a number of ARB-specific studies, however, show no discernible variation in 24-hour blood pressure or cardiovascular outcomes based on dose timing. Heterogeneous medication regimens, inconsistent use of ambulatory monitoring, and low power to identify cardiovascular endpoints in RAAS-specific trials all contribute to inconsistent and limited overall results.