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

Study objective: Our previous study demonstrated that 1 % diphenhydram ine is as effective as 1 % lidocaine for anesthesia in minor laceratio n repair, but that it also is more painful to inject. The purpose of t his study was to compare 0.5% diphenhydramine to 1 % lidocaine for pai n of injection and adequacy of local anesthesia. Study design: Randomi zed, double-blinded, prospective study from December 1991 through June 1992. Setting: University-affiliated, urban, inner-city emergency dep artment. Participants: Ninety-eight adults with linear skin laceration s without end-organ involvement were included; 48 received lidocaine a nd 50 received diphenhydramine. Interventions: Wounds were anesthetize d with either diphenhydramine or lidocaine according to a random table . Both patients and physicians rated the pain of injection and suturin g according to a standard, previously tested, visual analog scale. Mea surements 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 va riance were used to analyze the ranked sum scores. The power of the st udy to detect a ranked sum difference of 15 was 0.8 with P< .05 consid ered statistically significant. Lidocaine was found to be significantl y more effective as a local anesthetic for facial lacerations accordin g to both patients (P< .002) and physicians (P< .004). There was no st atistically significant difference between 1 % lidocaine and 0.5% diph enhydramine for pain of injection or suturing for all other locations according to both patients and physicians. Overall mean and median sco res for injection and suturing with diphenhydramine corresponded to th e mild pain category according to patients. Conclusion: Although not a replacement for lidocaine, diphen-hydramine is a viable alternative f or anesthesia in the repair of minor lacerations.