Safety of high-dose intravenous labetalol in hypertensive crisis

The study assesses the safety of high-dose intravenous (i.v.) labetalol in adults.

This is a retrospective administrative record review of 28 hospitals in one health care system, from October 2010 through October 2015. Patients were included if they received 300 mg of i.v. labetalol within a 24-hour period. Vital signs, adverse events and cumulative medication doses were obtained for up to 24 hours while on labetalol. Adverse events were defined as any systolic blood pressure measurement less than 90 mm Hg or heart rate less than 60 beats per minute.

We analyzed the records of 188 patients who received i.v. labetalol at higher than the maximum recommended dose of 300 mg. The mean dose of labetalol was 996 mg (range 300 to 4465 mg). The cumulative labetalol dose was not associated with adverse safety outcomes (p = 0.428), although eighty-one patients (44.3%) experienced adverse events. Sixty-six patients (36.5%) developed bradycardia and 34 patients (18.6%) developed hypotension. Only five patients (2.7%) required a rescue agent for refractory adverse events.

A retrospective review of high-dose i.v. labetalol hydrochloride with doses greater than 300 mg in 24 hours observed a high rate of bradycardia and hypotension, but the study found that these events rarely caused clinically significant hemodynamic compromise and was not statistically associated with adverse events.