Anesthetic efficacy of lidocaine/meperidine for inferior alveolar nerve blocks in patients with irreversible pulpitis

The purpose of this prospective, randomized, single-blind study was to compare the anesthetic efficacy of lidocaine with epinephrine to lidocaine plus meperidine with epinephrine for inferior alveolar nerve blocks (IAN) in patients with mandibular posterior teeth experiencing irreversible pulpitis. Forty-eight emergency patients diagnosed with irreversible pulpitis of a mandibular posterior tooth randomly received, in a single-blind manner, 36 mg of lidocaine with 18 mug epinephrine or 36 mg of lidocaine with 18 mug of epinephrine plus 36 mg meperidine with 18 mug epinephrine, using a conventional inferior alveolar nerve block. Endodontic access was begun 15 minutes after solution deposition, and all patients were required to have profound lip numbness. Success was defined as no or mild pain (visual analog scale recordings) upon endodontic access or initial instrumentation. The success rate for the inferior alveolar nerve block using the lidocaine solution was 26%, and for the lidocaine/meperidine solution, the success rate was 12%. There was no significant difference (p = 0.28) between the two solutions. In conclusion, for mandibular posterior teeth with irreversible pulpitis, the addition of 36 mg of meperidine to a lidocaine solution administered in a conventional IAN block did not improve the success rate over a standard lidocaine solution.