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The analgesic action of morphine‐N‐oxide
Author(s) -
FENNESSY M. R.
Publication year - 1968
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1968.tb07055.x
Subject(s) - morphine , tacrine , analgesic , pharmacology , potency , chemistry , medicine , in vitro , biochemistry , enzyme , acetylcholinesterase
1 The analgesic activity of morphine‐N‐oxide in mice and rats has been investigated and compared with that of morphine. 2 Both morphine and morphine‐N‐oxide were more active when given subcutaneously than when given intraperitoneally. 3 Given subcutaneously, morphine was 11–22 times more potent than morphine‐N‐oxide and when given intraperitoneally it was 39–89 times more potent. The potencies depended on the test situation and the species of animal used. 4 In animals pretreated with amiphenazole or tacrine, the analgesic activities of morphine and morphine‐N‐oxide were increased. The potencies of these analgesic drugs given intraperitoneally were increased to a greater extent than were the potencies obtained by subcutaneous administration. 5 A possible explanation for the increase in analgesic potency of morphine‐N‐oxide produced by pretreatment with amiphenazole or tacrine may be that morphine‐N‐oxide is rapidly inactivated in the liver and this inactivation is impaired by amiphenazole and tacrine.