Milrinone attenuates the negative inotropic effects of landiolol in halothane-anesthetized dogs.
BACKGROUND
Clinical use of high dose beta-blocker therapy is limited by excessive negative inotropic effects. Previous studies suggest that milrinone may be of utility in limiting the inotropic but not the chronotropic effects of beta blockers. We examined the hemodynamic effects of co-administration of a new potent selective beta(1) blocker, landiolol, and milrinone in halothane-anesthetized dogs.


METHODS
Eighteen adult mongrel dogs were anesthetized with 1.2 MAC halothane. Hemodynamic measurements were made at baseline, 30 min after starting the milrinone (0.5 micro g x kg(-1) x min(-1)) or normal saline infusion (n = 9 in each), then 30 min after each change in the dose of landiolol infusion. The tested doses of landiolol were 10, 100, and 1000 micro g x kg(-1) x min(-1).


RESULTS
Landiolol (>/= 10 micro g x kg(-1) x min(-1)) has significant and comparable negative chronotropic effects in both groups of dogs. While it also has significant negative inotropic effects in both groups, such effects are significantly attenuated in the dogs treated with milrinone.


CONCLUSIONS
Milrinone is effective to attenuate the negative inotropic effects of landiolol in halothane-anesthetized dogs.
Takahashi
Shinji
S
Department of Anesthesiology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Japan. shinjitk@md.tsukuba.ac.jp
Fujii
Yoshitaka
Y
Hoshi
Takuo
T
Uemura
Aki
A
Miyabe
Masayuki
M
Toyooka
Hidenori
H
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004285:Dogs; D006221:Halothane; D006339:Heart Rate / Q000187:drug effects; D020105:Milrinone / Q000494:pharmacology*; D009025:Morpholines / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D014508:Urea / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors* / Q000494:pharmacology*
D000319:Adrenergic beta-Antagonists; D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D009025:Morpholines; C077049:landiolol; D014508:Urea; D020105:Milrinone; D006221:Halothane