Cardiovascular and renal effects of carvedilol in dogs with heart failure.
To determine the acute effects of carvedilol (beta-blocker) on cardiovascular and renal function and its pharmacokinetics in dogs. Fifteen mature mongrel dogs (7-15 kg) of both sexes were used in these experiments. Eight dogs served as controls, and seven dogs served as iatrogenic mitral regurgitation (MR) experimental animals. Carvedilol (0.2, 0.4, and 0.8 mg/kg, P.O.) was administered, and the blood carvedilol concentration was analyzed by reverse-phase high-performance liquid chromatography. The response to isoproterenol or phenylephrine was also evaluated. Isoproterenol (0.025 microg/kg/min) was infused via the saphenous vein for 5 min, and phenylephrine (5 microg/kg) was injected with carvedilol (0.2, 0.4 mg/kg) or placebo for 4 days. The heart rate and arterial blood pressure were measured, and LV fractional shortening was measured by echocardiography. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured by intravenous infusion of sodium thiosulfate and sodium para-aminohippurate. Carvedilol (0.2 mg/kg) decreased the heart rate, whereas renal function, arterial blood pressure, and left ventricular contractile function were not affected. Carvedilol (0.4 mg/kg) decreased heart rate, blood pressure, and renal function. The tachycardic response to isoproterenol was significantly diminished for 36 hr by 0.4 mg/kg carvedilol. Carvedilol 0.2 mg/kg inhibited this effect for 24 hr. Thus, it is necessary to titrate the dosage of carvedilol, it should be initiated at less than 0.2 mg/kg and titrated up to 0.4 mg/kg for heart failure dogs.
Veterinary Teaching Hospital, School of Veterinary Medicine & Animal Science, Kitasato University, Towada, Aomori, Japan.
Masami
M
Uechi
Takahiro
T
Sasaki
Kouichiro
K
Ueno
Taiji
T
Yamamoto
Yumi
Y
Ishikawa
D000284:Administration, Oral; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002227:Carbazoles / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D000077261:Carvedilol; D004283:Dog Diseases / Q000188:drug therapy / Q000378:metabolism; D004285:Dogs; D004452:Echocardiography / Q000662:veterinary; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects / Q000662:veterinary; D006339:Heart Rate / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology; D007668:Kidney / Q000098:blood supply; D008297:Male; D008944:Mitral Valve Insufficiency / Q000188:drug therapy / Q000378:metabolism / Q000662:veterinary*; D010656:Phenylephrine / Q000494:pharmacology; D011412:Propanolamines / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D020257:Ventricular Remodeling / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D010656:Phenylephrine; D007545:Isoproterenol