Pain of Injection and Duration of Anesthesia for Intradermal Infiltration of Lidocaine, Bupivacaine, and Etidocaine

BACKGROUND: Bupivacaine and etidocaine are local anesthetics said to be long acting based on nerve block data. There are insufficient data on pain of infiltration and duration of anesthesia when either is used for dermal infiltration to assess suitability for skin surgery. OBJECTIVE: We conducted a randomized, placebo-controlled, double-blinded comparison of intradermal 1% etidocaine, 0.5% bupivacaine, and 2% lidocaine for pain of injection and duration of anesthesia. METHODS: Twenty subjects received the above three agents plus normal saline, each with and without epinephrine 1:200,000, with all solutions adjusted to pH 5.95 +/- 0.15. RESULTS: Lidocaine hurt least and etidocaine hurt most. Adrenalized solutions were more painful than plain. For plain solutions bupivacaine lasted longest and lidocaine lasted shortest by far. For adrenalized solutions bupivacaine lasted 27% longer than lidocaine and 45% longer than etidocaine. CONCLUSION: Where epinephrine is contraindicated and long anesthesia matters, use plain bupivacaine. When epinephrine can be used, lidocaine lasts almost as long as bupivacaine and hurts less.