Title Felypressin , but not epinephrine , reduces myocardial oxygen tension after an injection of dental local anesthetic solution at routine doses

Purpose: The aim of this study was to evaluate the effect of epinephrine (Epi) or felypressin (Fely) contained in dental local anesthetics on myocardial oxygen balance. Methods: Male Japan White tracheotomized rabbits were anesthetized with isoflurane. Three doses of 0.18, 0.36, and 0.72 ml of 2% lidocaine hydrochloride containing 1: 80,000 Epi or 3% prilocaine hydrochloride containing 0.03 IU/ml Fely were injected into the rabbit tongue muscle. These doses were equivalent to 2, 4, and 8 of dental local anesthetic cartridges in humans weighing 50 kg by body weight correction, respectively. Heart rate (HR), blood pressure, aortic blood flow (AoF), myocardial tissue blood flow (MBF) and myocardial tissue oxygen tension (PmO2) were continuously monitored. Data were recorded immediately before and 10, 20, 30 and 60 min after the injection. Results: HR decreased in Fely group. Systolic blood pressure elevated in Epi group, while diastolic blood pressure elevated in both groups. AoF and MBF increased while PmO2 did not change in Epi group. In contrast, AoF, MBF and PmO2 decreased in Fely group. Conclusion: It is suggested that Fely, but not Epi, would reduce myocardial oxygen tension and aggravate myocardial oxygen demand/supply balance even after an injection of dental local anesthetic solution at routine doses. 29th April, 2009 Dr. Leon A. Assael Editor-in-Chief Journal of Oral and Maxillofacial Surgery RE JOMS-D-09-00100: “Felypressin, But Not Epinephrine, Reduces Myocardial Oxygen Tension after an Injection of Dental Local Anesthetic Solution at a Routine Doses”