Vascular Reactions of Iodinated X-Ray Contrast Media: Mechanisms and Possible Therapeutic Interventions

Vascular reactions after administration of all classes of iodinated x-ray contrast media are well known side effects of these drugs. Both vasodilation and vasoconstriction have been observed. The manner and extent of the change in vessel tone depends on the type of contrast medium, species, vascular territory and contractile state of the vessels. The mechanisms underlying the vascular reaction induced by contrast media are currently not completely clear and studies on this question are partly contradictory or non-conclusive. Even if these side effects do not vitally compromise the patients, they are mainly responsible for patients' discomfort during examinations. To date, there are only a few possibilities to treat this type of side effect. In this review we describe the effects of high osmolar ionic, low osmolar non-ionic and isotonic contrast media on different vascular beds in humans and animals. Data from clinical and in vivo studies as well as from in vitro investigations on isolated organs and isolated vessel segments will be discussed. It will give an overview of the mechanistic explanations of the vascular reactions.