Iontophoretic administration of 2% lidocaine HCl and 1:100,000 epinephrine in humans

Objective: The primary objective was to evaluate the clinical safety and effectiveness of the iontophoretic administration of lidocaine HCl 2% and epinephrine 1:100,000 to induce local dermal anesthesia before intravenous (IV) cannulation. Design: Section I: Open, nonblinded. Section II: Randomized, double-blind, placebo-controlled. Setting: Section I: Healthy adult volunteers. Section II: Patients presenting for scheduled outpatient eye surgery. Patients: Section I: Seven healthy adult volunteers. Section II: Forty-four patients requiring IV cannulation before scheduled eye surgery. Interventions: Section I: Volunteers received iontophoresis of lidocaine HCl 2% with epinephrine 1:100,000 for a total delivery current of 40 mA . min. Section II: Patients received iontophoresis for a total delivery current of 40 mA min of lidocaine HCl 2% with epinephrine 1:100,000 (active) or saline (control) immediately before intravenous cannulation with a 20-gauge IV catheter. Major Outcome Measures: Section I: Venous blood plasma lidocaine levels, adverse events associated with iontophoresis. Section II: Patient and investigator assessment of analgesia, patient acceptance of iontophoresis, adverse events associated with iontophoresis. Results: Section I: No detectable levels of lidocaine were identified in any blood plasma sample. Adverse effects were minimal and transitory. Section II: Pain was decreased following lidocaine iontophoresis in comparison with controls, as determined by the patients and investigators. Iontophoresis was well accepted by the patients. Adverse effects were minimal and transitory. Conclusions: Iontophoresis of lidocaine 2% with 1:100,000 epinephrine for short delivery times does not lead to delivery of clinically important systemic levels of lidocaine in healthy adults. Iontophoresis of lidocaine 2% with 1:100,000 epinephrine provides adequate skin anesthesia for placement of peripheral small-gauge IV catheters.