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Effect of heparin on digitoxin protein binding
Author(s) -
Lohman Joseph J H M,
Hooymans Piet M,
Koten Marli L P,
Verhey Maurice T J M,
Merkus Frans W H M
Publication year - 1985
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1985.11
Subject(s) - digitoxin , heparin , chemistry , lipolysis , free fraction , in vivo , pharmacology , in vitro , medicine , plasma protein binding , endocrinology , biochemistry , adipose tissue , biology , digoxin , heart failure , microbiology and biotechnology
Reduction of digitoxin binding to plasma proteins after heparin has been reported. Our aim was to determine whether this reduction is an in vivo effect or occurs only after blood collection as a result of heparin‐induced lipolysis that increases levels of nonesterified fatty acids in vitro. The effect of heparin on digitoxin protein binding was studied in 10 patients undergoing hemodialysis receiving digitoxin maintenance therapy. Digitoxin free fraction increased after heparin, from 2.5% ± 0.7% to 4.4% ± 1.1%, but after inhibition of in vitro lipolysis with diethyl p ‐nitrophenyl phosphate (2mM), a potent lipase inhibitor, there was no increase in the free fraction (2.3% ± 0.4% before heparin and 2.4% ± 0.5% after heparin). Digitoxin salivary levels were also unchanged (0.41 ± 0.08 ng/ml before heparin and 0.41 ± 0.08 ng/ml after heparin [n = 8]). These data indicate that the binding of digitoxin to plasma proteins in vivo is not altered by heparin. The reduced binding reported elsewhere was a result of heparin‐induced in vitro lipolysis. Clinical Pharmacology and Therapeutics (1985) 37, 55–60; doi: 10.1038/clpt.1985.11