Addition of morphine to local anesthetic infiltration does not improve analgesia after pediatric dental extractions

BACKGROUND: Opioid receptors have been noted in the peripheral nerve endings of afferent neurons. Blockade of these receptors with peripherally administered opioids is believed to result in analgesia. METHODS: In a prospective, randomized, double-blind study, we studied the analgesic effects of adding a subsystemic dose of morphine to local anesthetic infiltration (lidocaine hydrochloride) during pediatric dental extractions. Forty-two subjects, aged 2-7 years of ASA physical status I-II, were randomized to receive submucous infiltration with either morphine 25 microg.kg(-1) in 2% lidocaine hydrochloride with 1 : 1 00 000 epinephrine (morphine group) or 2% lidocaine hydrochloride with 1 : 1 00 000 epinephrine (control group) at the end of surgery. RESULTS: There was no difference in postoperative analgesic requirements within the first 24 h. In-hospital acetaminophen consumption was 85% in the morphine group compared with 81% in the control group. CONCLUSION: We conclude that there is no benefit of adding a subsystemic analgesic dose of morphine to local anesthetics for analgesia after dental extractions in children.