Landiolol, an ultra-short-acting beta 1-adrenoceptor antagonist, does not alter the electroencephalographic effect of isoflurane in swine model.
BACKGROUND
beta-Adrenergic blocking agents may interact with anaesthetics, and several studies suggest that beta-blockers attenuate electroencephalographic responses during general anaesthesia. We have investigated the influence of landiolol, an ultra-short-acting beta 1-adrenoceptor antagonist, on the electroencephalographic effect of isoflurane in pigs.


METHODS
Ten swine were anaesthetized through inhalation of 2% isoflurane. The inhalational concentration was then decreased to 0.5% and maintained for 25 min, before being returned to 2% and maintained for a further 25 min (control period). After control measurements, infusion of landiolol (at 0.125 mg kg(-1) min(-1) for 1 min, and then at 0.04 mg kg(-1) min(-1)) was started. After a 20 min stabilization period, the inhalational concentration was varied as in the control period (40 gamma landiolol). Finally, infusion of landiolol was increased from 0.04 to 0.2 mg kg(-1) min(-1), and after a 20 min stabilization period, the inhalational concentration was again varied as in the control period (200 gamma landiolol). End-tidal isoflurane concentrations and spectral edge frequencies were recorded throughout the study. Analysis of the pharmacodynamics was performed using a sigmoidal inhibitory maximal effect model for spectral edge frequency vs effect-site concentration.


RESULTS
There were no significant differences in the effect of isoflurane among the conditions used. Landiolol did not shift the concentration-effect relationship [the effect-site concentration that produced 50% of the maximal effect was 1.35 (0.17)% under control conditions, 1.30 (0.12)% at 40 gamma landiolol, and 1.38 (0.30)% at 200 gamma landiolol].


CONCLUSIONS
Landiolol does not alter the electroencephalographic effect of isoflurane.
Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine 1-20-1 Handayama, Hamamatsu 431-3192, Japan. tadkur@hama-med.ac.jp
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Kurita
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Morita
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Fukuda
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Takata
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Uraoka
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Sanjo
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Sato
D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004569:Electroencephalography / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D007530:Isoflurane / Q000494:pharmacology*; D023421:Models, Animal; D009025:Morpholines / Q000494:pharmacology*; D013552:Swine; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology
D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists; D018685:Anesthetics, Inhalation; D009025:Morpholines; C077049:landiolol; D014508:Urea; D007530:Isoflurane