Celiprolol: a positive inotropic β‐adrenoceptor blocking agent in conscious dogs

Abstract

3 Intravenous injection of celiprolol (3 mgkg-') in nine dogs, increased LV dP/dt by 13 + 2.6%, velocity of shortening (LV dD/dt) by 9.2 + 3.4%, and heart rate by 19 + 4.6% and decreased LV end-diastolic diameter by 1.8 + 0.8%, all significantly (P < 0.05). Celiprolol blocked the inotropic actions of isoprenaline (0.5 ygkg-') but only partially reduced its hypotensive effects. Propranolol, in contrast, reduced LV dP/dt by 17 + 3.3% and heart rate by 8.1 + 2.7% (P < 0.05) while totally abolishing the hypotension, tachycardia and increase in LV dP/dt caused by isoprenaline. Following fi-adrenoceptor blockade with propranolol and with heart rate held constant by electrical pacing, celiprolol increased LV dP/dt by 16 + 4.0%, LV dD/dt by 12 + 3.0% and reduced LV end-diastolic diameter by 3.5 + 0.5% (P < 0.05). 4 Thus, in conscious dogs, celiprolol increases inotropic state and reduces preload independently of fl-adrenoceptor mechanisms and the Bowditch phenomenon, while effectively blocking fil-receptors in the heart. These properties would make celiprolol useful in patients where a conventional f-adrenoceptor blocking agent might lead to pump failure.