Objective: To assess the pharmacokinetics, safety, and tolerability of lidocaine delivered via 4 lidocaine 5% patches applied for 18 h/d for 3 consecutive days in healthy volunteers.
Methods: A prospective, nonrandomized, open-label trial was conducted to determine the pharmacokinetics of 4 lidocaine patches 5% applied to the backs of 20 volunteers on days 1, 2, and 3. On each day, serum samples were collected prior to, during, and after patch application. Safety and tolerability assessments included skin evaluations, monitoring of clinical adverse events and vital signs, 12-lead electrocardiograms, and laboratory testing.
Results: For days 1, 2, and 3, the mean +/- SD maximum concentrations were 145.1 +/- 42.4, 153.0 +/- 40.7, and 153.8 +/- 51.4 ng/mL, respectively; the median times to peak plasma concentration were 18.0, 16.5, and 16.5 hours, respectively; the mean +/- SD trough concentrations were 83.0 +/- 29.0, 85.7 +/- 31.1, and 77.0 +/- 26.9 ng/mL, respectively; and the mean +/- SD AUCs over 24 hours were 2089.2 +/- 632.5, 2659.2 +/- 726.8, and 2675.7 +/- 819.2 ng.h/mL, respectively. The patch was well tolerated; local skin reactions were generally minimal and self-limited.
Conclusions: The application of 4 lidocaine patches 5% for 18 h/d for 3 consecutive days is well tolerated; steady-state plasma concentrations are achieved within 3 days. Maximum plasma concentrations of lidocaine are similar to those reported in a previous study with 3 lidocaine patches 5% applied for 12 h/d for 3 consecutive days.