title: Effects of epinephrine on lidocaine pharmacokinetics and blood volume in the dental pulp.
abstract: BACKGROUND
  Epinephrine potentiates and prolongs the efficacy of local anesthetics by reducing blood flow. We investigated the effect of epinephrine on the pharmacokinetics of lidocaine and the pulpal blood volume after maxillary infiltration anesthesia in rats.
  
  
  METHODS
  We measured the (14)C-radioactivity and (14)C-distribution in the maxilla and the dental pulp after the injection of 2% (14)C-lidocaine with or without 10 μg/mL epinephrine (n = 7) into the palatine mucosa proximal to the first molar. The blood volume in the pulp was measured using (99m)Tc-pertechnetate (n = 5).
  
  
  RESULTS
  When lidocaine was injected together with epinephrine, the lidocaine became widely distributed throughout the maxilla and was observed mainly in the first molar pulp. The lidocaine amount in the dental pulp at 10-60 minutes was more than 2 times higher than that after the injection of lidocaine alone. The relative pulpal blood volume after 20 minutes decreased to 63.1% of the value after the injection of lidocaine alone.
  
  
  CONCLUSIONS
  We found that lidocaine had infiltrated into the molar pulp after infiltration anesthesia. Furthermore, our results suggested that epinephrine augmented the retention of lidocaine in the pulp.
authors.affiliation: Research Center for Odontology, Tokyo, Japan. Electronic address: shuichi@tky.ndu.ac.jp.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Department of Anesthesiology, The Nippon, Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan.
authors.forename: Mikiko
authors.initials: M
authors.lastname: Yamashiro
authors.affiliation: Department of Anesthesiology, The Nippon, Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan.
authors.forename: Kyohei
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Department of Anesthesiology, The Nippon, Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Yasuda
authors.affiliation: Department of Anesthesiology, The Nippon, Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Sunada
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D001345:Autoradiography / Q000379:methods; D001810:Blood Volume / Q000187:drug effects; D002250:Carbon Radioisotopes; D003782:Dental Pulp / Q000098:blood supply / Q000378:metabolism*; D004837:Epinephrine / Q000494:pharmacology*; D004911:Erythrocyte Volume / Q000187:drug effects; D007267:Injections; D008012:Lidocaine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D008437:Maxilla / Q000098:blood supply / Q000378:metabolism; D008852:Microradiography / Q000379:methods; D008963:Molar / Q000098:blood supply / Q000378:metabolism; D019275:Radiopharmaceuticals; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects; D013670:Sodium Pertechnetate Tc 99m; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D000779:Anesthetics, Local; D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D014662:Vasoconstrictor Agents; D008012:Lidocaine; D013670:Sodium Pertechnetate Tc 99m; D004837:Epinephrine
keywords: Autoradiography; infiltration anesthesia; lidocaine amount in pulp; pulpal blood volume; rat; vasoconstrictive effect of epinephrine