EXPERIENCE WITH THE AVOIDANCE OF ALLERGIC REACTIONS TO PYELOGRAPHIC MEDIA BY THE USE OF ANTIHISTAMINE DRUGS

AH contrast media used for excret.ory pyelograms evoke undesirable side reactions in some patients. Many are mild and transient reactions, such as flushing, a feeling of warmth, metallic taste, arm pain, nausea, and vomiting. The more serious side reactions include urticaria, asthma, and shock; 011 rare occasions these result in death. Recently new compounds have been developed that consistently yield pyelograms of excellent quality and also appear to evoke fewer reactions than compounds earlier available.' 3 I recently collected data on the occurrence of severe reactions from members of the American Association of Genito-Urinary Surgeons, Boston, illass. The purpose of the survey was to determine, from the experience of these urologists, the value of tests for predicting reactions, as well as to discover the prevalent attitude on the value of antihistamine drugs in their prevention. A report of this survey will be published in the proceedings of the association. TABLE 3 shows the data obtained from the survey. The majority of those reporting expressed some degree of enthusiasm regarding the lack of reactions that have occurred with the new agents, yet there is about a 1-in-500 over-all incidence of severe reactions, and none of the compounds is free of this risk. The death occurred in a case where 1 cc. of Hypaque was int.roduced intravenously as a test, and no reaction occurred. The final injection was given 4.5 min. later and, within 5 min. the patient had a circulatory collapse. Oxygen, intravenous fluids, and Neo-Synephrine were administ.ered and, finally, cardiac massage by the open method was done. An authority3 in the field of allergy research has informed me that this death probably was not due to an antigen-. antibody or histamine release mechanism for the reason that no reaction of an allergic nature was evoked by the preliminary test dose. I t was postulated that a serotonin or a direct cellular histamine or some other chemical release might have been the basis for the reaction, and that it probably would not have been prevented by antihistamine injection. Another possibility is that t.he newer urographic media may have some direct depre ing effect upon the cardiovascular system similar to the effects of Diodrast. rious investigators4, have demonstrated that Diodrast is a potent vasodilating agent. that produces a fall in blood pressure and changes in the arterial pulse contour. The Diodrast reaction, particularly in humans, is suggestive of a parasympathetic discharge such as would occur, for example, after the administration of acetyl-betamethylcholine. The effects are a drop in blood pressure, bradycardia, nausea, flushing, cough, dyspnea, and sweating. Gordon el a1.6 (1950), who studied the effects of Diodrast in animals, were unable to prevent their occurrence with atropine, vagotomy, or tetraethylammonium and concluded that the peripheral