Dosing Recommendations for Hypertensive Emergencies

Labetalol Dosing

The American Heart Association recommends labetalol should be initiated at 0.3-1.0 mg/kg (maximum 20 mg) as a slow IV bolus every 10 minutes, or as a continuous infusion at 0.4-1.0 mg/kg/hour up to 3 mg/kg/hour, with a maximum cumulative dose of 300 mg 1
Initial bolus of labetalol is 0.25-1.0 mg/kg (typically 20 mg for an 80 kg patient) administered as slow IV injection, with repeat dosing of 40-80 mg every 10 minutes as needed 1
Maximum cumulative dose of labetalol is 300 mg total, which can be repeated every 4-6 hours 1
Absolute contraindications for labetalol include second or third-degree heart block, bradycardia, decompensated heart failure, reactive airways disease (asthma, COPD) 1, 2, 3

The American College of Cardiology recommends nicardipine should be initiated at 5 mg/hour IV infusion and titrated by 2.5 mg/hour every 5-15 minutes to a maximum of 15 mg/hour until desired blood pressure is achieved 1, 4
Initial rate of nicardipine is 5 mg/hour, with titration increments of 2.5 mg/hour every 5-15 minutes 1, 4
Maximum dose of nicardipine is 15 mg/hour 1, 4
Conversion from oral nicardipine to IV is as follows: oral 30 mg TID = IV 1.2 mg/hour, oral 40 mg TID = IV 2.2 mg/hour 4

Standard norepinephrine dosing for hypotension follows established critical care protocols, with an initial rate of 0.01-0.05 mcg/kg/min (typically start at 2-4 mcg/min for average adult) 1
Titration of norepinephrine is by 0.05-0.1 mcg/kg/min every 5-10 minutes, with a typical range of 0.05-0.5 mcg/kg/min 1
Maximum dose of norepinephrine is up to 3 mcg/kg/min in refractory shock (though doses >1 mcg/kg/min suggest need for additional interventions) 1

Nicardipine inhibits CYP3A4, significantly elevating immunosuppressant levels (cyclosporine and tacrolimus), requiring frequent monitoring of trough levels 4
Cimetidine increases nicardipine levels, requiring careful monitoring if used concomitantly 4