Digoxin toxicity is a common and important cause of adverse drug events in the elderly US population. The serum and central nervous system (CMS) concentrations of digoxin are affected by p-glycoprotein (P-gp), which regulates gastrointestinal absorption, renal elimination, and CMS penetration of digoxin. The variability in P-gp activity caused by either genetic mutation or concomitant medications has not been studied in a population receiving digoxin clinically. Advancing knowledge of the role of P-gp in clinical digoxin toxicity will assist in elucidating the etiology of toxicity, which may ultimately lead to interventions to reduce the risk of digoxin toxicity. The primary aim of the proposed case-control study is to examine the relationship, in an elderly patient population, between clinical digoxin toxicity and genotypic differences in the multi-drug resistance-1 (MDR1) gene which encodes P-gp.
The second aim i s to characterize the effect of concomitant drug therapy with P-gp inhibition activity. In addition to improving the safety of digoxin, the - Pharmacoepidemiology study will foster career development in a promising young investigator. The results may advance the safety of several therapeutic agents through understanding the biology of P-gp.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32AG026180-01
Application #
6934365
Study Section
Epidemiology of Clinical Disorders and Aging Study Section (ECDA)
Program Officer
Nayfield, Susan G
Project Start
2005-07-01
Project End
2007-06-30
Budget Start
2005-07-01
Budget End
2006-06-30
Support Year
1
Fiscal Year
2005
Total Cost
$73,975
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Haynes, K; Heitjan, Df; Kanetsky, Pa et al. (2008) Declining public health burden of digoxin toxicity from 1991 to 2004. Clin Pharmacol Ther 84:90-4
Leonard, Charles E; Haynes, Kevin; Localio, A Russell et al. (2008) Diagnostic E-codes for commonly used, narrow therapeutic index medications poorly predict adverse drug events. J Clin Epidemiol 61:561-71
Haynes, K; Hennessy, S; Morales, K H et al. (2008) Inter-rater reliability of a classification system for hospital adverse drug event reports. Clin Pharmacol Ther 83:485-8