PHARMACOLOGICAL PROPERTIES OF ANTIHISTAMINE DRUGS, BENADRYL, PYRIBENZAMINE AND XEOAXTERGAN

Comparisons have been made of the effects of antihistamine drugs on the depressor and spasmogenic actions of histamine in dogs since the resultant data would aid in evaluating such drugs relative to their use as pharmacological tools for determining the role of histamine in physiological and pathological processes. Furthermore, a study of these and other pharmacological and toxicological data with relation to therapeutic effectiveness of the various antihistamine drugs and to side-actions and toxicity should aid in selection of even more useful antihistamine drugs. The antagonism of the vascular effects of histamine assumes added significance in view of the recent reports that antihistamine drugs are therapeutically effective in allergic diseases (for refer-ences cf. 1-7) such as dermatoses, urticaria, and hay fever. Vascular reactions are undoubtedly fundamentally related to the major symptoms of allergy (8). The antihistamine drugs were also studied relative to their influence on the actions of acetylcholine and epinephrine on blood pressure, and their action on smooth muscle activity of the uterus and duodenum, since earlier studie