• Accelerated hypertension
• Aortic dissection

• Labetalol hydrochloride injection 100 mg in 20 mL ampoule (5 mg/mL)

• Glucose 5%
• Labetalol hydrochloride is incompatible with sodium bicarbonate 4.2%

• Ensure patient remains supine during and for 3 hr after end of administration
  • avoids excessive postural hypotension
• Monitor blood pressure
  • 5 minutes after any bolus injection or commencing infusion or rate change 
  • check BP every 15-30 minutes thereafter
• Monitor heart rate after injection and during infusion
  • in most patients, a small decrease in heart rate
• Control severe bradycardia (unusual) by giving atropine sulphate 600 microgram by IV injection
  • repeat if necessary, at 5-min intervals
  • do not exceed a total dose of 2.4 mg atropine sulphate
• Watch for signs of bronchospasm, especially in patients with reduced respiratory function

• Aim to reduce diastolic BP to 110-115 mmHg over several hours
• Labetalol can be given by either IV injection or IV infusion

IV bolus injection

• Initially 50 mg (10 mL) of labetalol hydrochloride over at least 1 min
• Maximum effect usually occurs within 5 min
• Effective duration of action is usually about 6 hr, but can be as long as 18 hr
• If necessary, repeat after 5 min
• if still no response, again 10 and 15 min after initial dose
• Total dose should not exceed 200 mg

IV infusion via a syringe pump

• Withdraw 100 mL from a 500 mL bag of glucose 5%
• Add 5 × 100 mg vials of labetalol (100 mL) to the bag and mix well. 500 mg in 500mL = 1 mg/mL
• Diluted solution is stable for 24 hr

Starting dose

• Start with 0.5 mg/min by IV infusion
• lower rate commenced to avoid hypotension

Rate change

• Increase according to response to maximum of 2 mg/min
• Continue infusion at selected rate until satisfactory response, then stop
• Effective cumulative dose is usually 50-200 mg
• occasionally requires higher doses

Labetalol IV infusion and flow rates