Intrathecal chlorprothixene, cis(z)-flupenthixol, chlorpromazine and fluphenazine for prolonged spinal blockades of sensory and motor functions in rats

摘要

The aim of this study was to examine whether thioxanthine-type antipsychotics (chlorprothixene and cis(z)-flupenthixol) and phenothiazine-type antipsychotics (chlorpromazine and fluphenazine) produced spinal anesthesia. Using a rat model of intrathecal injection, we evaluated spinal anesthesia of antipsychotic drugs (chlorprothixene, cis(z)-flupenthixol, chlorpromazine, and fluphenazine) and bupivacaine, a known local anesthetic. At a same dose of 2.31 μmol/kg, chlorprothixene had the most potent spinal blockades (P0.001) and the longest duration of action (P0.001) of motor function and nociception among those antipsychotic drugs. On the 50 effective dose (ED 50) basis, the ranks of potencies were chlorprothixene= bupivacainecis(z)-flupenthixolchlorpromazinefluphenazine (P0.01 for the differences) in dose-response studies. At an equianesthetic basis (ED 25, ED 50, and ED 75), the spinal block duration caused by chlorprothixene, cis(z)-flupenthixol, chlorpromazine or fluphenazine was longer than that caused by bupivacaine (P0.05). These results showed that chlorprothixene produced a similar potency and longer duration of spinal anesthesia than did bupivacaine, whereas several other antipsychotics produced less potency than did bupivacaine.