55 Should I give digoxin to patients with heart
failure if they are in sinus rhythm? If so, to whom?
Are there dangers to stopping it once started?
Lionel H Opie
This is a very contentious issue. It is well known that the only
prospective trial that was powered for mortality, failed to show
that digoxin could lessen deaths.^1 On the other hand, hospitali-
sation from all causes, including cardiovascular, was reduced by
6%. Personally, bearing in mind all the hazards of digoxin, I
would rather add to the basic diuretic-ACE inhibitor therapy,
spironolactone in a low dose (25mg daily). The latter improves
mortality substantially, as shown in the RALES study.^2
Or, if I had the patience and skill, and the patient is haemo-
dynamically stable, I would add a beta blocker such as bisoprolol,
metoprolol or carvedilol, starting in a very low dose given to a
haemodynamically stable patient and working up the dose over 2
to 3 months. Any doubt about the mortality benefit of beta
blockade has been removed by the recent CIBIS study.^3 If after all
this I was still looking for further improvement, I would certainly
add digoxin but take great care to avoid overdosing, which can be
fatal, especially in the presence of a low plasma potassium level.
Once I had started digoxin, I would not hesitate to stop it if
toxicity were suspected. But if the patient came to me already
taking digoxin with a low therapeutic blood level, and seemed to
be doing well, then I would not stop the drug. The problems with
digoxin withdrawal suggested by the withdrawal trials such as
RADIANCE is that they merely show that patients who do well
while on digoxin, should not have it withdrawn.^4 These are non-
randomised trials and give no information on how the patients
reacted to the addition of digoxin. For example, to take an
extreme case, if digoxin had potentially adverse effects, and
actually killed patients, such an increase of mortality could not be
detected by assessing the effects of withdrawal of the drug from
the survivors.
RReeffeerreenncceess
1 The effect of digoxin on mortality and morbidity in patients with
heart failure. The Digitalis Investigation Group. N Engl J Med
1997; 333366 : 525–33.