Emergency phenytoin loading by constant intravenous infusion

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Neurology

Background:

• Phenytoin is a critical anti-seizure medication.
• Achieving therapeutic phenytoin levels rapidly is essential for effective seizure control.
• Traditional phenytoin administration methods may have limitations in speed and predictability.

Purpose of the Study:

• To assess the efficacy and safety of a constant intravenous (IV) infusion method for phenytoin loading.
• To determine the rate of achieving therapeutic phenytoin blood levels with this infusion method.
• To identify and characterize complications associated with continuous-infusion phenytoin loading.

Main Methods:

• Prospective evaluation of 38 patients receiving a total dose of 18 mg/kg phenytoin via constant IV infusion.
• Phenytoin administered as 500 mg in 50 mL normal saline at an initial rate of 40 mg/min.
• Cardiac rhythm monitored by telemetry; vital signs and rhythm strips obtained every 15 minutes; blood levels drawn at various intervals post-infusion.

Main Results:

• Therapeutic phenytoin blood levels (>10 micrograms/mL) achieved in 97% of patients.
• Transiently toxic phenytoin levels observed post-infusion in 22 patients and at 4 hours in 16 patients.
• Minor complications included IV site irritation and a slight decrease in blood pressure; seizures occurred in two patients requiring additional medication.

Conclusions:

• Constant intravenous phenytoin infusion is an effective method for rapid achievement of therapeutic drug levels.
• The method is generally well-tolerated, with manageable side effects.
• This infusion strategy offers a reliable approach for phenytoin loading in clinical practice.