title: Pharmacologic alterations in Tc-99m binding by red blood cells: concise communication.
abstract: The effect of two antihypertensive agents (captopril and prazosin) and of digoxin on the efficiency of Tc-99m binding to RBCs was evaluated in the rat. RBCs were labeled with Tc-99m in vivo in six groups of rats: I-normotensive controls Wistar rat (WR), II-prazosin treated WR, III-spontaneously hypertensive rat (SHR), IV-prazosin-treated SHR, V-digoxin-treated WR, and VI-captopril-treated WR. The percentage of intravascular Tc-99m bound to RBC (%T) and the percentage of injected dose remaining intravascular 5 min after injection (%i.v.) were determined. Mean %T was 94.2, 83.8, 94.9, 86.1, 79.7, and 93.3 for groups I-VI respectively. Mean %I.V. was 96.4, 74.6, 94.9, 79.0, 74.4, and 87.4 for groups I-VI respectively. The findings demonstrate a significant reduction of RBC tagging with Tc-99m in rats treated with prazosin and digoxin but not with captopril. The data suggest a potential interference by patient medication with the performance of blood-pool studies.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D004077:Digoxin / Q000494:pharmacology*; D004347:Drug Interactions; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006400:Hematocrit; D006973:Hypertension / Q000378:metabolism; D011224:Prazosin / Q000494:pharmacology*; D011392:Proline / Q000031:analogs & derivatives*; D011485:Protein Binding; D011799:Quinazolines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013667:Technetium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D013997:Time Factors
chemical_list: D011799:Quinazolines; D004077:Digoxin; D013667:Technetium; D011392:Proline; D002216:Captopril; D011224:Prazosin