1-PERCENT LIDOCAINE VERSUS 0.5-PERCENT DIPHENHYDRAMINE FOR LOCAL-ANESTHESIA IN MINOR LACERATION REPAIR

Study objective: Our previous study demonstrated that 1 % diphenhydramine is as effective as 1 % lidocaine for anesthesia in minor laceration repair, but that it also is more painful to inject. The purpose of this study was to compare 0.5% diphenhydramine to 1 % lidocaine for pain of injection and adequacy of local anesthesia. Study design: Randomized, double-blinded, prospective study from December 1991 through June 1992. Setting: University-affiliated, urban, inner-city emergency department. Participants: Ninety-eight adults with linear skin lacerations without end-organ involvement were included; 48 received lidocaine and 50 received diphenhydramine. Interventions: Wounds were anesthetized with either diphenhydramine or lidocaine according to a random table. Both patients and physicians rated the pain of injection and suturing according to a standard, previously tested, visual analog scale. Measurements and main results: Patient and physician ratings were ranked without regard to treatment group, and rank sum scores were calculated for each group. General linear models and multivariate analysis of variance were used to analyze the ranked sum scores. The power of the study to detect a ranked sum difference of 15 was 0.8 with P< .05 considered statistically significant. Lidocaine was found to be significantly more effective as a local anesthetic for facial lacerations according to both patients (P< .002) and physicians (P< .004). There was no statistically significant difference between 1 % lidocaine and 0.5% diphenhydramine for pain of injection or suturing for all other locations according to both patients and physicians. Overall mean and median scores for injection and suturing with diphenhydramine corresponded to the mild pain category according to patients. Conclusion: Although not a replacement for lidocaine, diphen-hydramine is a viable alternative for anesthesia in the repair of minor lacerations.