Prilocaine versus plain or buffered lidocaine for local anesthesia in laceration repair: randomized double-blind comparison.

AIM To compare the effectiveness of 2% prilocaine plain solution, 1% lidocaine hydrochloride, and 1% buffered lidocaine in local anesthesia and pain reduction during injection in laceration repair. METHODS A double-blind randomized prospective comparison study included 183 consecutive eligible adult patients with simple lacerations, admitted to the emergency department between January 2001 and June 2002. Each of the three groups of patients received different local anesthetic before laceration suturing (1% lidocaine, 2% prilocaine, or buffered 1% lidocaine). The patients were asked to assess the pain intensity on a 0-100 numerical rating scale at the site of needle entry into the skin (P1), immediately after the completion of injection (P2), and after the first puncture of the suturing needle (P3). The differences among the three patient groups were tested with one-way analysis of variance and chi-square test. RESULTS The three groups of 61 patients each (one patient declined from prilocaine group) did not significantly differ in mean P1 scores (29.1+/-20.9 in the prilocaine, 32.2+/-22.9 in the lidocaine, and 33.2+/-21.7 in the buffered lidocaine group; p=0.56). Mean P2 scores were highest in the prilocaine group (24.0+/-16.0), followed by lidocaine (20.9+/-14.9) and buffered lidocaine (16.1+/-11.3) groups (p=0.007). Mean P3 score was significantly lower in the lidocaine group (13.4+/-11.3) then in the prilocaine (18.4+/-13.1) and buffered lidocaine (20.4+/-16.2) groups (p=0.014). The number of patients who required additional anesthetic administration in each group was not significantly different (p=0.09). CONCLUSION Injection of 1% lidocaine was associated with lower pain ratings on suturing needle puncture than with 2% prilocaine or buffered 1% lidocaine.