Drugs That May Affect Radiopharmaceutical Distribution/Labeling in Cardiac Ejection Fraction Imaging Studies Using  ^99mTc RBC

Causative Drug

Appearance on Scintiphotos or Effect on Labeling

Adriamycin

Decreased RBC labeling efficiency; abnormal response to exercise by left ventricle

Calcium channel blockers

Appearance of normal exercise test in presence of CAD

β- Blockers

Decreased wall motion with exercise

Cessation of thyroxine

Increased thyroid uptake

Digoxin

Decreased RBC labeling efficiency

Doxorubicin

Decreased RBC labeling efficiency

Heparin

Decreased RBC labeling efficiency

Hydralazine

Decreased RBC labeling efficiency; poor cardiac border definition

Iodinated radiopaque contrast media

Decreased ABC labeling efficiency contrast media

Methyldopa

Decreased RBC labeling efficiency due
to induced RBC antibody formation; poor cardiac border definition

Prazocin

Decreased RBC labeling efficiency

Propranolol

Decreased ABC labeling efficiency; false negative response to exercise; masks CAD

Quinidine

Decreased ABC labeling efficiency due to induced ABC antibody formation