Significant hypotension following oral dipyridamole administration prior to thallium scintigraphy in physically limited patients

Dipyridamole has liberalized the referrals for stress thallium examinations. Blood pressure (BP) readings at 5-minute intervals for 1 hour after dipyridamole administration were compared with clinical status. Results have been reviewed in 120 physically limited patients after an average oral dose of 5.4 mg/kg. Of these patients, 109 had a BP decline from 137 ± 21/82 ± 12 mm Hg to 113 ± 21/70 ± 13 mm Hg (mean ± SD); 47 had a systolic BP decline of over 20 mm Hg, 18 over 40 mm Hg, and 13 over 50 mm Hg. BP decline was not significantly correlated with concomitant cardiovascular medications, ST segment changes, symptoms (excluding lightheadedness), or referral source. Hypotension is relatively common but unpredictable after oral dipyridamole