title: Effect of spironolactone, potassium canrenoate, and their common metabolite canrenone on Dimension Vista Digoxin Assay.
abstract: Spironolactone, a potassium sparing diuretic metabolized to canrenone, is often used with digoxin to treat various conditions including congestive heart failure. Potassium canrenoate is a similar drug that is also metabolized to canrenone. Due to reported interference of spironolactone, potassium canrenoate, and their common metabolite canrenone with digoxin immunoassays, we investigated potential interference of these compounds with Dimension Vista Digoxin immunoassay using Flex reagent cartridge. Aliquots of a drug-free serum pool were supplemented with various amounts of spironolactone, potassium canrenoate, or canrenone and apparent digoxin values were measured using Dimension Vista digoxin assay, we observed none-detected value except when aliquots were supplemented with higher amounts of spironolactone or canrenone. Similarly, when aliquots of a serum digoxin pool (prepared by pooling specimens from patients receiving digoxin) where further supplemented with various amounts of spironolactone, potassium canrenoate, or canrenone, we observed moderately falsely elevated digoxin values only in specimens containing higher amounts of spironolactone or canrenone. We conclude that spironolactone and canrenone but not potassium canrenoate may cause modest interference with Dimension Vista digoxin assay but such interferences may not be clinically significant except with very high amounts of canrenone.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School and Laboratory Services, Memorial-Hermann Hospital at Texas Medical Center, Houston, Texas 77030, USA. Amitava.Dasgupta@uth.tmc.edu
authors.forename: Amitava
authors.initials: A
authors.lastname: Dasgupta
authors.forename: Myrtle J
authors.initials: MJ
authors.lastname: Johnson
mesh_terms: D001681:Biological Assay; D002191:Canrenoic Acid / Q000097:blood / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology*; D002192:Canrenone / Q000097:blood* / Q000737:chemistry* / Q000276:immunology; D002316:Cardiotonic Agents / Q000097:blood / Q000494:pharmacology*; D002624:Chemistry, Clinical / Q000379:methods; D003429:Cross Reactions; D004077:Digoxin / Q000097:blood* / Q000737:chemistry* / Q000276:immunology; D004347:Drug Interactions; D016903:Drug Monitoring; D006801:Humans; D007118:Immunoassay / Q000379:methods; D000451:Mineralocorticoid Receptor Antagonists / Q000097:blood* / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D009994:Osmolar Concentration; D011933:Reagent Kits, Diagnostic; D013148:Spironolactone / Q000097:blood* / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism
chemical_list: D002316:Cardiotonic Agents; D000451:Mineralocorticoid Receptor Antagonists; D011933:Reagent Kits, Diagnostic; D013148:Spironolactone; D004077:Digoxin; D002192:Canrenone; D002191:Canrenoic Acid