General pharmacological actions of traxanox sodium. II. Effects on the cardiovascular system

The effects of traxanox, an anti-allergic drug, on the cardiovascular system were studied in both anesthetized dogs and cats and in isolated heart preparations from guinea-pigs. In anesthetized dogs, a very small dose of traxanox (0.01 mg/kg, i.v.) had no effect, but 0.1--30 mg/kg caused an increase in respiratory rate, hypotension, bradycardia, a transient decrease followed by an increase in renal blood flow, and a decrease in femoral blood flow. These effects were abolished by vagal block, indicating they are mediated via vagal afferents. In contrast, oral administration of traxanox (100 mg/kg) had no effect on the blood pressure or heart rate of anesthetized dogs. In anesthetized cats, traxanox (3 and 30 mg/kg, i.v.) caused a slight increase in blood pressure, but showed no effect on respiratory rate and heart rate. Both traxanox and theophylline (10(-4)M) caused increases in the beat rate of the atria and the contractile force of the papillary muscle in isolated preparations from guinea-pigs, and they potentiated the positive chronotropic and inotropic responses induced by isoproterenol. On the other hand, in anesthetized and vagotomized dogs, traxanox (3 and 10 mg/kg, i.v.) affected neither the left ventricular contractile...Continue Reading