Doxepin has a potent and long-acting spinal anesthetic effect in rats.
Doxepin, a tricyclic antidepressant, was recently found to be effective in the treatment of various acute and chronic painful conditions. However, the mechanism of its actions was not clear, especially when involving the spine. The aim of our study was to evaluate the spinal anesthetic effect of doxepin. Two commonly used traditional local anesthetics, bupivacaine and lidocaine, were used as controls. The potencies and durations of the drugs' action were evaluated in male Sprague-Dawley rats. We found that intrathecally administered doxepin, like bupivacaine and lidocaine, produced dose-related spinal anesthetic effects on motor activity, proprioception, and nociception. Among the three drugs, doxepin produced spinal anesthetic effects in rats more potent than that of lidocaine (p < 0.001, in each comparison) and longer than that of bupivacaine and lidocaine (p < 0.001, in each comparison). The spinal activity of doxepin may provide some explanation of its clinical effect in pain management.
Department of Surgery, Chi-Mei Medical Center, Tainan, Taiwan.
Bor-Chin
BC
Cheng
Bing-Ren
BR
Chan
Yu-Wen
YW
Chen
Koung-Shing
KS
Chu
Kuang-I
KI
Cheng
Jhi-Joung
JJ
Wang
Chin-Chen
CC
Chu
D000775:Anesthesia, Spinal; D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004316:Doxepin / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D000929:Antidepressive Agents, Tricyclic; D004316:Doxepin