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.
Cheng
Bor-Chin
BC
Department of Surgery, Chi-Mei Medical Center, Tainan, Taiwan.
Chan
Bing-Ren
BR
Chen
Yu-Wen
YW
Chu
Koung-Shing
KS
Cheng
Kuang-I
KI
Wang
Jhi-Joung
JJ
Chu
Chin-Chen
CC
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