The negative predictive value of typing safe local anesthetics.

Background: Although allergy to local anesthetics (LA) is rare, patients often report unwanted reactions after their administration. A history of anaphylaxis or an atypical reaction related to LA is an indication for typing a safe anesthetic for future surgical or dental procedures.

Aim: The aim of the study was to determine the negative predictive value (NPV) of typing safe LA.

Methods: A total of 154 patients with a history of an unwanted reaction to LA were enrolled into the study. Stepwise typing of a safe anesthetic included skin prick tests (SPT) and intracutaneous tests (ICT) with two or three of the following LA: lidocaine, bupivacaine, mepivacaine, and articaine. Skin tests were followed by provocations with one or two LA. Telephone follow-up visits were performed 4-12 months after drug typing. On the basis of follow-up questionnaire results, the NPV of the protocol was calculated.

Results: The full protocol was performed in 148 patients. Positive results of SPT were observed in 2, of ICT in 19 and of provocations in 11 cases. Lidocaine was found safe in 44, bupivacaine in 14, mepivacaine in 34 and articaine in 61 patients. The drug typed at the clinical visit was administered in 78 patients, and 76 reported no reactions (NPV = 97%).

Conclusion: Stepwise approach including SPT, ICT and provocations is safe and allows typing a safe anesthetic in a vast majority of patients.