A comparison of tablets with oral suspension formulation of dipyridamole in thallium myocardial imaging.

Dipyridamole stress thallium imaging has been widely employed to diagnose and assess the extent of coronary heart disease in patients who cannot exercise. When oral dipyridamole administration was used, a wide range of results for sensitivity, specificity, hemodynamic response and side effect profile has been reported. The authors hypothesized that the formulation used for oral administration of dipyridamole plays a major factor in this variability, and that the pulverized form of dipyridamole will achieve faster and more consistent response than the standard tablet form. The authors studied 13 consecutive patients who underwent thallium scintigraphy. Eight patients received dipyridamole pulverized and dissolved in a glycol/aqueous base diluent (group A), and five patients received the standard form of dipyridamole (group B). In group A, mean peak systolic blood pressure decreased from 142 +/- 31 (mean +/- standard deviation) to 109 +/- 30 (P = .05), and mean diastolic blood pressure decreased from 76 +/- 14 to 51 +/- 5. The mean heart rate changed from 78 +/- 26 to 80 +/- 10. In group B, baseline systolic blood pressure was 165 +/- 12 and decreased to 156 +/- 7 at 45 minutes and to 155 +/- 14 at 90 minutes. Heart rate increased from baseline of 69 +/- 9 to 75 +/- 8 at 45 minutes and to 76 +/- 11 at 90 minutes. At 45 minutes, the systolic blood pressure of the 8 group A patients dropped by 33 +/- 19 mm Hg, whereas group B's changed by 9 +/- 6 mm Hg (P less than .005).(ABSTRACT TRUNCATED AT 250 WORDS)