Nighttime dosing assures postdistribution sampling for therapeutic drug monitoring of digoxin.
To study the appropriateness of phlebotomy for digoxin therapeutic drug monitoring (TDM) in outpatients, we conducted a retrospective chart review, a computer search of all previous TDM testing, and a questionnaire of all outpatients (n = 86) who had serum digoxin determinations between April 10 and April 28, 1992 (585 tests). In patients who took digoxin at the same time daily (40 patients, 300 tests), 52% of tests were performed on inappropriate samples drawn within 6 h of the last dose. No patient who took digoxin after 1700 had inappropriate tests. Phlebotomy for serum digoxin determinations before distribution of digoxin is complete is a common problem in outpatients, leading to clinically uninterpretable test results. Postdistribution sampling can be assured by nighttime dosing, and this recommendation has been implemented at our hospital.
Bernard
D W
DW
Department of Pathology and Laboratory Medicine, University of Pennsylvania Medical Center, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
Bowman
R L
RL
Grimm
F A
FA
Wolf
B A
BA
Simson
M B
MB
Shaw
L M
LM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004077:Digoxin / Q000008:administration & dosage* / Q000097:blood / Q000627:therapeutic use; D004334:Drug Administration Schedule; D005260:Female; D016231:Fluorescence Polarization Immunoassay; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
D004077:Digoxin