IV Labetalol Vial Strengths
Labetalol for intravenous use is commercially available as 5 mg/mL concentration in either 20-mL vials (100 mg total) or 40-mL vials (200 mg total). 1
Standard Vial Configurations
- 20-mL vials contain 100 mg of labetalol HCl (5 mg/mL concentration) 1
- 40-mL vials contain 200 mg of labetalol HCl (5 mg/mL concentration) 1
Preparation for Continuous Infusion
When preparing labetalol for continuous IV infusion, the FDA label describes two standard methods using these vial sizes:
Method 1: Add contents of either two 20-mL vials (40 mL total) or one 40-mL vial to 160 mL of IV fluid to create 200 mL solution containing 200 mg labetalol (1 mg/mL final concentration) 1
Method 2: Add contents of either two 20-mL vials (40 mL total) or one 40-mL vial to 250 mL of IV fluid to create solution containing 200 mg labetalol (approximately 2 mg/3 mL final concentration) 1
Clinical Context
The 5 mg/mL concentration allows for precise bolus dosing, starting with 20 mg (4 mL) administered over 2 minutes, with subsequent doses of 40 mg (8 mL) or 80 mg (16 mL) at 10-minute intervals up to a maximum cumulative dose of 300 mg 1
For continuous infusion, the diluted solution (1 mg/mL) should be administered at 2 mL/min to deliver 2 mg/min 1