RT Journal Article
SR Electronic
T1 Isobolographic Analysis of Epinephrine With Bupivacaine, Dextromethorphan, 3-Methoxymorphinan, or Dextrorphan on Infiltrative Anesthesia in Rats: Dose-Response Studies
JF Regional Anesthesia & Pain Medicine
JO Reg Anesth Pain Med
FD BMJ Publishing Group Ltd
SP 115
OP 121
DO 10.1136/rapm-00115550-200803000-00005
VO 33
IS 2
A1 Yu-Wen Chen
A1 Kuo-Sheng Liu
A1 Jhi-Joung Wang
A1 Willy Chou
A1 Ching-Hsia Hung
YR 2008
UL http://rapm.bmj.com/content/33/2/115.abstract
AB Background and Objectives: The aims of this study were to establish the potencies of epinephrine, bupivacaine, dextromethorphan, 3-methoxymorphinan, and dextrorphan and evaluate interactions of epinephrine with bupivacaine, dextromethorphan, 3-methoxymorphinan, or dextrorphan as an infiltrative anesthetic. Bupivacaine, a common and long-acting local anesthetic, was used as control.Methods: Dose-dependent responses of epinephrine, dextromethorphan, 3-methoxymorphinan, and dextrorphan on cutaneous analgesia were compared with bupivacaine in rats. The interactions of drugs were evaluated via an isobolographic analysis.Results: We found that epinephrine, bupivacaine, dextromethorphan, 3-methoxymorphinan, and dextrorphan produced a dose-dependent local anesthetic effect as infiltrative cutaneous analgesia. Relative potencies were epinephrine > bupivacaine > dextromethorphan > 3-methoxymorphinan > dextrorphan (P < .01 for each comparison). Coadministration of bupivacaine with epinephrine produced a synergistic effect, and coadministration of dextromethorphan, 3-methoxymorphinan, or dextrorphan with epinephrine produced an additive effect.Conclusions: Epinephrine, dextromethorphan, 3-methoxymorphinan, and dextrorphan are known to have local anesthetic effects as infiltrative cutaneous analgesia in rats. Epinephrine increased the potency of bupivacaine, but not dextromethorphan, 3-methoxymorphinan, or dextrorphan as an infiltrative anesthetic. The cutaneous analgesic effects of adding epinephrine to dextromethorphan, 3-methoxymorphinan, or dextrorphan, are similar to combinations of 2 local anesthetics.