Preparation for administration: Labetalol hydrochloride injection is prepared for continuous intravenous infusion by diluting the contents with commonly used intravenous fluids.
The contents of either two 20 mL vials (40 mL), or one 40 mL vial, are added to 160 mL of a commonly used intravenous fluid, such that the resultant 200 mL of solution contains 200 mg of labetalol hydrochloride, 1 mg/mL.
The diluted solution should be administered at a rate of 2 mL/min to deliver 2 mg/min.
Alternatively, the contents of either two 20 mL vials (40 mL), or one 40 mL vial, of labetalol hydrochloride are added to 250 mL of a commonly used intravenous fluid. The resultant solution will contain 200 mg of labetalol hydrochloride, approximately 2 mg/3 mL to deliver approximately 2 mg/min.
Note: Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
Blood pressure monitoring: Immediately before the injection and at 5 and 10 minutes after injection, supine blood pressure should be measured to evaluate response.
The blood pressure should be monitored during and after completion of the infusion or intravenous injections. Rapid or excessive falls in either systolic or diastolic blood pressure during intravenous treatment should be avoided. In patients with excessive systolic hypertension, the decrease in systolic pressure should be used as an indicator of effectiveness in addition to response of the diastolic pressure.
Compatibility with commonly used intravenous fluids: Labetalol hydrochloride injection was tested for compatibility with commonly used intravenous fluids at final concentrations of 1.25 to 3.75 mg of labetalol hydrochloride per mL of the mixture. Labetalol hydrochloride was found to be compatible with and stable (for 24 hours refrigerated or at room temperature) in mixture with the following solutions: Ringer's injection, Lactated ringer's injection, 5% dextrose and ringer's injection, 5% Lactated ringer's and 5% Dextrose injection, 5% Dextrose injection, 0.9% Sodium chloride injection, 5% Dextrose and 0.2% Sodium chloride injection, 2.5% Dextrose and 0.45% Sodium chloride injection, 5% Dextrose and 0.9% Sodium chloride injection, 5% Dextrose and 0.33% Sodium chloride injection.
Incompatibilities: Labetalol hydrochloride incompatible with 5% sodium bicarbonate injection. Labetalol hydrochloride solutions containing 1.25-3.75 mg/mL in 5% sodium bicarbonate have a pH of 7.6-8 and from a white precipitate, probably the free bases within 6 hours after admixture. A white precipitate also has been observed following concomitant infusion of other alkaline drugs (e.g., furosemide) and labetalol hydrochloride injection; therefore, labetalol hydrochloride should not be given in the same infusion line with other alkaline solutions.