Objective: To determine whether topical tetracaine attenuates the pain of buffered lidocaine infiltration.
Methods: A prospective, randomized, double-blind trial was conducted involving adults with lacerations being repaired following local anesthesia. Two 0.5-mL injections of buffered lidocaine were given in a standardized manner. Injection 1 was given prior to application of topical study solution. Injection 2 was given on the opposite side of the laceration after topical application of a study solution that was 4 mL of either tetracaine or normal saline. Pain of each infiltration was measured using a visual analog pain scale. Pain score differences (injection 1 - injection 2) were compared for the 2 study solutions using a Wilcoxon 2-sample signed-rank test.
Results: Of 57 subjects studied, 29 received tetracaine and 28 received saline. The groups were similar in age, gender, wound length, wound location, and initial pain score. Pain scores decreased significantly in the tetracaine group as compared with the saline group. The median pain score difference for tetracaine was 12.0 mm, with an interquartile range (IQR) of 2 to 43 mm, as compared with 2 mm, with an IQR of —17 to 21 mm for saline (p = 0.048).
Conclusion: Topical tetracaine attenuates the pain of infiltration of buffered lidocaine.