I. Ragueneau et al., Pharmacokinetic and pharmacodynamic drug interactions between digoxin and macrogol 4000, a laxative polymer, in healthy volunteers, BR J CL PH, 48(3), 1999, pp. 453-456
Aims The aim of this study was to examine the bioequivalence between a sing
le oral dose of digoxin administered alone and with a coadministration of m
acrogol 4000 (a laxative polymer) in 18 healthy volunteers.
Methods This was an open, randomised, two-way cross-over study, with a sing
le dose oral administration of 0.5 mg digoxin administered alone or in comb
ination with macrogol 4000, 20 g day(-1) during 8 days. Pharmacokinetics of
digoxin, heart rate and PR ECG interval at rest were assessed.
Results Macrogol 4000 coadministration was associated with a 30% decrease o
f digoxin AUC and a 40% decrease in its C-max (P<0.05). Digoxin t(max) and
t(1/2,z) were nor significantly altered. Heart rate and PR interval did not
differ during the two therapeutic sequences, digoxin alone and digoxin in
combination.
Conclusions Macrogol 4000 coadministration interacts with single-dose digox
in pharmacokinetics. This is most likely due to a reduction of the intestin
al absorption of digoxin. However, there was no consequence of this interac
tion on heart rate and AV conduction.