Efficacy and Safety of Immediate-Release Nifedipine in Critically Ill Patients

Background: Immediate-release nifedipine (IRN) is a calcium channel blocker with potent vasodilatory and antihypertensive properties. Safety concerns led to a black box warning for increased risk of myocardial infarction, stroke, and arrhythmias. Objective: The aim of this study was to evaluate the safety and efficacy of IRN for acute blood pressure lowering in critically ill patients. Methods: A retrospective, single-center study was performed in critically ill patients who received at least one dose of IRN. The primary endpoint was the change in systolic blood pressure (SBP) measured at baseline and 1 hour after first administration of IRN. Secondary outcomes included clinically significant hypotension, defined as an absolute reduction in SBP ≥ 15% or vasopressor initiation within 1 hour after administration; incidence of arrhythmias, stroke, or myocardial injury; and time to transition off antihypertensive infusions. Results: IRN resulted in a median [interquartile range] SBP change of -10 [-21 to -1] mmHg between baseline 142 mmHg [124-155] and 1 h post-administration 127 mmHg [114-144]; P < .001. Twenty-seven percent of patients experienced clinically significant hypotension, with hypotension observed in 24% and vasopressors initiated in 4% of patients. Sixteen percent of patients experienced new-onset arrhythmia and 18% experienced myocardial injury following IRN during hospitalization. Median time to transition off intravenous (IV) continuous infusion antihypertensives was 8.5 [0-31.5] hours. Conclusion: IRN led to a reduction in SBP which may have been associated with clinically significant hypotension and need for vasopressor support. Further studies with direct comparisons to alternatives are needed to determine the true association of adverse events with IRN.