How do you prepare a labetalol drip?

How to Prepare a Labetalol Drip

Prepare labetalol continuous infusion by adding 200 mg (either two 20-mL vials or one 40-mL vial) to 160 mL of compatible IV fluid to create a 200 mL solution containing 1 mg/mL, then infuse at 2 mL/min to deliver 2 mg/min. 1

Standard Preparation Methods

The FDA-approved drug label provides two specific preparation protocols 1:

Method 1 (1 mg/mL concentration - Preferred):

• Add 40 mL of labetalol injection (200 mg total) to 160 mL of IV fluid 1
• Final volume: 200 mL containing 200 mg labetalol (1 mg/mL) 1
• Infusion rate: 2 mL/min delivers 2 mg/min 1

Method 2 (Alternative concentration):

• Add 40 mL of labetalol injection (200 mg total) to 250 mL of IV fluid 1
• Final volume: 290 mL containing approximately 2 mg/3 mL 1
• Infusion rate: 3 mL/min delivers approximately 2 mg/min 1

Compatible IV Fluids

Labetalol is stable for 24 hours (refrigerated or at room temperature) when mixed with 1:

• 0.9% Sodium Chloride (Normal Saline) 1
• 5% Dextrose in Water (D5W) 1
• Lactated Ringer's 1
• Ringer's Injection 1
• 5% Dextrose and 0.2%, 0.33%, 0.45%, or 0.9% Sodium Chloride combinations 1
• 2.5% Dextrose and 0.45% Sodium Chloride 1

Critical Incompatibility:

Do NOT mix labetalol with 5% Sodium Bicarbonate—it is incompatible 1

Titration Protocol

Starting the Infusion:

• Begin at 2 mg/min and adjust according to blood pressure response 1
• Use a controlled administration mechanism (graduated burette or infusion pump) for precise delivery 1
• Continue infusion until satisfactory response is achieved, then transition to oral labetalol 1

Effective Dose Range:

• Typical effective IV dose: 50-200 mg total 1
• Maximum total dose: up to 300 mg may be required 1

Critical Monitoring Requirements

Patient Positioning:

Keep patients supine during the entire period of IV administration 1

• Expect substantial fall in blood pressure when standing 1
• Establish patient's ability to tolerate upright position before allowing ambulation 1

Blood Pressure Monitoring:

• Monitor continuously during infusion 1
• Avoid rapid or excessive falls in systolic or diastolic pressure 1
• In excessive systolic hypertension, use systolic pressure decrease as an indicator of effectiveness in addition to diastolic response 1

Pharmacokinetic Considerations

• Half-life: 5-8 hours, meaning steady-state levels will not be reached during usual infusion periods 1
• Onset of action occurs within minutes of starting infusion 2
• The drug undergoes significant hepatic first-pass metabolism (approximately 85% removed in single liver passage) 3

Common Pitfalls to Avoid

• Never use 5% Sodium Bicarbonate as the diluent—this is the only incompatible solution 1
• Do not allow patients to ambulate without first testing upright tolerance—postural hypotension is the most troublesome side effect 1, 4
• Avoid in patients with heart block, bradycardia, decompensated heart failure, or reactive airways disease 5
• Always inspect the solution visually for particulate matter and discoloration before administration 1

Transition to Oral Therapy

Once supine diastolic blood pressure begins to rise 1:

• Start with 200 mg oral labetalol 1
• Follow with additional 200-400 mg in 6-12 hours based on blood pressure response 1
• Subsequent titration can proceed with twice-daily dosing (200 mg, 400 mg, 800 mg, or 1200 mg b.i.d.) 1