Contractile and electrical activities of dexchlorpheniramine on rat hearts

Abstract

Dexchlorpheniramine is a first-generation H1-Antihistamine, and despite numerous studies on the cardiotoxicity of other first-generation H1-Antihistamines, the effects of dexchlorpheniramine on cardiac physiology are not well known. The objective of the present study was to characterize the action of dexchlorpheniramine on the amplitude of the force of contraction, and on the electrocardiographic parameters in isolated and perfused hearts of Wistar rats. The Langendorff isolated perfused heart technique was performed and the effects of dexchlorpheniramine (3-300μmol/L, n=6) on the cardiac contraction and on the RR, QRS, QT and QTc parameters of the electrocardiogram were measured. The RR, QRS, and QT intervals increased by dexchlorpheniramine, not being so with the QTc interval. This probably suggests some type of action of dexchlorpheniramine on cardiac K+ and Na+ channels. The amplitude of the cardiac force of contraction decreased in concentration dependent manner, which suggests some effect on the Ca2+ current by dexchlorpheniramine. The IC50 estimated for the inhibition of the cardiac force of contraction was 4.12±1.64μmol/L.