Landiolol, an ultra short-acting beta1-adrenoceptor antagonist, does not alter the minimum alveolar anesthetic concentration of isoflurane in a swine model.
BACKGROUND
We previously reported that landiolol, an ultra-short-acting beta1-adrenoceptor antagonist, does not alter the electroencephalographic effect of isoflurane. Here, we investigated the influence of landiolol on the minimum alveolar anesthetic concentration (MAC) of isoflurane required to prevent movement in response to a noxious stimulus in 50% of subjects.


METHODS
Ten swine (29.0 +/- 3.4 kg) were anesthetized by inhalation of isoflurane. MAC was determined using the dewclaw clamp technique, in which movement in response to clamping is recorded. After determination of MAC in the baseline period, an infusion of landiolol (0.125 mg x kg(-1) x min(-1) for 1 min, then 0.04 mg x kg(-1) x min(-1)) was started. After a 20-min stabilization period, MAC was again assessed (0.04 mg x kg(-1) x min(-1) landiolol). The infusion of landiolol was then increased from 0.04 to 0.2 mg x kg(-1) x min(-1), and after a 20-min stabilization period, MAC was again assessed (0.2 mg x kg(-1) x min(-1) landiolol). Finally, the infusion of landiolol was stopped, and after a 20-min stabilization period, MAC was assessed for a fourth time (Baseline 2).


RESULTS
Landiolol clearly attenuated the increases in heart rate and mean arterial blood pressure that occurred in response to the dewclaw clamp, but did not alter the MAC of isoflurane.


CONCLUSIONS
Landiolol does not alter the antinociceptive effect of isoflurane. This result, combined with that from our previous work, also suggests that landiolol does not influence the anesthetic potency of inhaled anesthetics.
Kurita
Tadayoshi
T
Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Japan. tadkur@hama-med.ac.jp
Takata
Kotaro
K
Uraoka
Masahiro
M
Morita
Koji
K
Sato
Shigehito
S
D000280:Administration, Inhalation; D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003243:Consciousness / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D007530:Isoflurane / Q000008:administration & dosage / Q000378:metabolism*; D023421:Models, Animal; D009025:Morpholines / Q000494:pharmacology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism; D013552:Swine; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology
D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists; D018685:Anesthetics, Inhalation; D009025:Morpholines; D018342:Receptors, Adrenergic, beta-1; C077049:landiolol; D014508:Urea; D007530:Isoflurane