Contrast media and bronchospasm: a study with iopamidol.

Conventional radiological contrast media given intravenously are known to produce bronchospasm in the majority of patients, even though this is rarely clinically apparent. We have found that this phenomenon is much less pronounced with the new, low-osmolality contrast medium iopamidol. If the mechanism underlying the clinically silent bronchospasm observed with the conventional media is the same as that underlying the occasional life-threatening or fatal bronchospasm, then this observation is of considerable importance.