Disposition of tablet and capsule formulations of digoxin in the elderly.
OBJECTIVE
To compare digoxin tablets and liquid-filled capsules with respect to excretion of the drug and its metabolites in urine and feces at steady state.


METHODS
A randomized, crossover trial, each period lasting 3 weeks, with no washout period.


METHODS
A university hospital.


METHODS
Six patients, five of whom were elderly, with histories of gastrointestinal disorders, such as hypochlorhydria, intestinal bacterial overgrowth, and inflammatory bowel disease.


METHODS
The patients received digoxin once/day in either tablet or capsule form for 3 weeks, and then were switched to the other formulation. Total urinary and fecal excretion from the last 3 days of each regimen were analyzed for the drug and metabolites.


RESULTS
No statistically significant differences were found between tablets and capsules in recovery of digoxin or its metabolites in urine or feces (p = 0.05). One subject had a 4-fold increase in urinary drug excretion and 50% decrease in fecal excretion after taking the capsules compared with tablets. Intersubject variability in extent and type of metabolite excretion was greater than intrasubject variability.


CONCLUSIONS
Fecal analyses may be an accurate way to classify patients as formers of digoxin reduction products.
Hui
J
J
College of Pharmacy, Ohio State University, Columbus 43210.
Wang
Y M
YM
Chandrasekaran
A
A
Geraets
D R
DR
Caldwell
J H
JH
Robertson
L W
LW
Reuning
R H
RH
D000368:Aged; D000369:Aged, 80 and over; D002214:Capsules; D002626:Chemistry, Pharmaceutical; D018592:Cross-Over Studies; D004077:Digoxin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005243:Feces / Q000737:chemistry; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D013607:Tablets; D014556:Urine / Q000737:chemistry
D002214:Capsules; D013607:Tablets; D004077:Digoxin