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Basic Science (26)
Author(s) -
Khodorova Alla B.,
Strichartz Gary R.
Publication year - 2001
Publication title -
pain practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 58
eISSN - 1533-2500
pISSN - 1530-7085
DOI - 10.1111/j.1533-2500.2001.1011-26.x
Subject(s) - medicine , anesthesia , analgesic , motor block , bupivacaine , pharmacology
The addition of dilute epinephrine produces equieffectivenes of bupivacaine enantiomers for cutaneous analgesia in the rat. (Brigham and Women's Hospital, Boston, MA) Anesth Analg 2000;91:410–416. This study investigated the effectiveness for cutaneous analgesia of bupivacaine (Bup) stereoisomers in male rats. As a model of infiltration anesthesia, inhibition of a nocifensive reflex by subcutaneous injection of 0.6mL of different concentrations of R‐, S‐, and racemic‐Bup was evaluated quantitatively by the fraction of times a pinprick failed to evoke a nocifensive motor response. R‐Bup was more potent in the extent of the block; however, S‐Bup had a longer‐lasting action at smaller doses. This significant difference was apparent when R‐Bup and S‐Bup were administered in equipotent doses of 0.06% and 0.075%, respectively. Co‐injection of epinephrine (Epi) with these equipotent doses enhanced and prolonged the blocking effects of both Bup stereoisomers, although the dilutions of 1:100,000 to 1:1,000,000 Epi itself induced partial, transient analgesia. At 1:2,000,000 dilution, Epi alone had no analgesic effect; however, when co‐injected with the shorter‐acting R‐Bup (0.06%), Epi prolonged its blocking effect to equal the duration of the block evoked by equipotent S‐Bup (0.075%). Conclude that R‐Bup is more potent for cutaneous analgesia and that the longer duration of the block by S‐Bup probably originates from vasoconstrictor activity.