“Representative isobolograms plotted for each drug interaction illustrate that a beta-adrenoceptor agonist (isoproterenol), selective beta 2-adrenoceptor agonists (salbutamol, terbutaline), alpha 1- and alpha 2-adrenoceptor antagonists yohimbine , phentolamine, prazosin), as well as the stimulant caffeine, strongly potentiate the lethal effect of PB.”