Dipyridamole Thallium-201 Myocardial Imaging Complications Associated with Oral and Intravenous Routes of Administration

Previous reports have shown that TI-201 myocardial imaging with either an oral or intravenous administration of dipyridamole is a suitable diagnostic examination for patients at risk for coronary artery disease who cannot perform treadmill exercise. To compare the incidence of complications associated with these two routes of drug administration, the records of 78 oral and 97 intravenous dipyridamole TI-201 imaging studies were reviewed. The oral administration is associated with a significantly higher incidence of nausea (15% vs. 4%). Despite the higher incidence of nausea, the percentage of patients having one or more dipyridamole-induced symptoms was no greater for the oral (29%) than for the intravenous (37%) administration. Intravenous administration produced both a significantly higher incidence of atypical angina (14% vs. 4%) and a significantly greater increase in heart rate (16.6 vs. 10.2 beats per minute). No patient in either the oral or intravenous dipyridamole protocols had life-threatening arrhythmias or myocardial infarctions. In clinical practice, the difference in complications associated with the oral and intravenous administration of dipyridamole for TI-201 imaging is not significant.