Clinical Chemistry Email Content Delivery
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Clinical Chemistry 44: 1883-1885, 1998;
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Submit an electronic Letter to
the Editor about this paper
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (11)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Valdes, R.
Right arrow Articles by Jortani, S. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Valdes, R., Jr.
Right arrow Articles by Jortani, S. A.
Related Collections
Right arrow Laboratory Management
Right arrow Drug Monitoring and Toxicology
(Clinical Chemistry. 1998;44:1883-1885.)
© 1998 American Association for Clinical Chemistry, Inc.

Editorial

Monitoring of Unbound Digoxin in Patients Treated with Anti-Digoxin Antigen-binding Fragments: A Model for the Future?

Roland Valdes, Jr.1,2,a, and Saeed A. Jortani1

Departments of
1 Pathology and Laboratory Medicine and ,
2 Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40292
a Author for correspondence. Fax 502-852-1771; e-mail rvaldes@louisville.edu.

Digoxin is one of the few therapeutic drugs for which antidotal therapy is available (1) . Administration of Fab fragments has successfully been used to reverse the effects of life-threatening digoxin overdoses for over 20 years. Digoxin-specific Fab fragments are produced by cleaving sheep digoxin-specific IgG with papain to form two Fab fragments (50 000 Da each) and one 50 000-Da Fc fragment (2) . As determined by equilibrium dialysis with one such preparation of Fab fragments, the intrinsic affinity constant for binding of digoxin was 1010 L/mol (3) . Depending on the experimental conditions used (e.g., K+ concentration and type of membrane isolated), the affinity constant for binding of digoxin to its receptor (the sodium pump) has been reported to be in the range 106-108 L/mol (4)(5) . The rationale for using Fab fragments to reduce toxic effects of digoxin is their greater affinity for digoxin when compared with the sodium pump. As a consequence, the extracellular unbound digoxin concentration is lowered, and further equilibration of receptor-bound digoxin with the fluid in the extracellular space leads to the eventual release of digoxin from its receptor sites. The affinity of digitoxin for binding to Fab fragments is 10-fold lower than that of digoxin; however, it is high enough to allow clinical utility of Fab fragments in cases of digitoxin intoxication as well (3) .

The dose of Fab fragments should be approximately equimolar to the total body digoxin load, which is determined according to the serum digoxin concentration and/or patient's medical history (6) . Digibind® (Glaxo Wellcome) is the most common brand of anti-digoxin Fab fragments used in the United States and worldwide. Boehringer-Mannheim also produces anti-digoxin Fab fragments intended for use as an antidote. . . . [Full Text of this Article]


References




The following articles in journals at HighWire Press have cited this article:


Home page
 Clin. Chem.Home page
G. A. McMillin, W. E. Owen, T. L. Lambert, B. K. De, E. L. Frank, P. R. Bach, T. M. Annesley, and W. L. Roberts
Comparable Effects of DIGIBIND and DigiFab in Thirteen Digoxin Immunoassays
Clin. Chem., September 1, 2002; 48(9): 1580 - 1584.
[Full Text] [PDF]

Home page
 Clin. Chem.Home page
W. Steimer, C. Muller, and B. Eber
Digoxin Assays: Frequent, Substantial, and Potentially Dangerous Interference by Spironolactone, Canrenone, and Other Steroids
Clin. Chem., March 1, 2002; 48(3): 507 - 516.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1998 by the American Association for Clinical Chemistry.