Pulmonary function (specifically, forced expiratory volume in 1 sec and forced expiratory flow at low lung volumes) was measured with maximal expiratory flow-volume curves during excretory urography in 70 patients and during sham procedures in 27 subjects. Forty-one patients received a 100 ml intravenous bolus of 60% methylglucamine diatrizoate and 29 patients received 100 ml of 50% sodium diatrizoate. Within 20 min, greater than 95% of patients had bronchospasm as indicated by asymptomatic decreases in pulmonary function. These decreases were significantly (p less than 0.001) greater than in the subjects undergoing sham procedures. Greater than 50% of patients had a maximum decrease in pulmonary function that exceeded the range of variability for consecutive repetitions of maximal expiratory flow-volume curves. These patients were classified as responders during excretory urography. The prevalence of responders was similar in methylglucamine diatrizoate and sodium diatrizoate patients. The magnitude of maximum decreases in pulmonary function did not differ significantly between methylglucamine diatrizoate and sodium diatrizoate responders.
Conclusions: Sodium diatrizoate does not offer an advantage over methylglucamine diatrizoate with respect to asymptomatic bronchospasm during excretory urography.