Neutralizing pH of lidocaine reduces pain during Norplant system insertion procedure.

The acidity of lidocaine used as a local anesthetic during the insertion of Norplant System capsules can cause patient discomfort. Buffering lidocaine with sodium bicarbonate significantly reduced pain scores reported by 46 women who participated in this randomized, double-blind study. Derived from a pain scale of 1 to 10, the mean difference in reported pain scores with and without buffering was 1.17 (P = 0.0098) with women using themselves as controls, for an average reduction in pain of 29%. Because this added step minimized patient discomfort, it might make the Norplant System a more attractive option for women apprehensive about insertion pain.