When I first had afib over 18 years ago, I went from paroxysmal to a 2 1/2 month persistent episode within 2 months of my first episode. I went to a highly recommended cardiologist as the second cardio I'd gone to. He immediately told me that digoxin was his favorite afib med. I'd already found this site and I read the founder of this board, Hans Larsen's book, " Lone-Atrial-Fibrillation-Towards-Cure" [
www.amazon.com]
I refused the med based on what I'd read. The cardio & I had several hour long discussions. Finally, he got frustrated with me and referred be to the EP in the practice. When I told him my afib story, he said, "You obviously have vagally mediated afib and there are certain meds we won't prescribe (i.e. digoxin). I had to bite my tongue to not suggest he give the cardio an inservice on afib meds.
Below is from p78 of the book (p 90 of the PDF).
Special Note on Digoxin
Digoxin (digitalis, Lanoxin), originally derived form the foxglove plant, has been in use for 200 years as a heart medication. The primary indication for digoxin is in the treatment of heart failure (congestive heart failure) especially if accompanied by atrial fibrillation. From this original application digoxin has expanded into the treatment of atrial fibrillation and lone atrial fibrillation. Most medical textbooks still laud digoxin as an effective drug for heart failure. Does it actually work?
The Digitalis Investigation Group, a large team of American and Canadian researchers released a major report, which presents the findings of a large, randomized, double-blind, placebo-controlled trial of digoxin in the treatment of heart failure patients. The three-year trial involved over 7000 patients with heart failure (left ventricular ejection fraction less than 0.45). The patients were divided randomly into two equal-sized groups with one group receiving 0.250 mg of digoxin per day and the other group receiving a placebo; all patients in both groups continued on ACE inhibitors and diuretics. The average follow-up time was 37 months. At the end of the trial 35% of the participants had died in each group. The death rate attributable to worsening heart failure was slightly less in the digoxin group, but the number of deaths from other cardiovascular events such as arrhythmias and strokes was higher. Patients on digoxin were less likely to be admitted to hospital for worsening heart failure (26.8 versus 34.7% for controls), but had higher admission rates for suspected digoxin toxicity (2.0 versus 0.9%).
The researchers conclude that digoxin does not reduce the risk of death from heart failure or other causes, but that it does reduce the rate of hospital admissions, especially for worsening heart failure. In other words, while digoxin may, to some extent, ameliorate the symptoms of heart failure it does not reverse or cure it nor does it reduce the risk of death from this condition[12,13].
British researchers followed 484 heart failure patients for three years and found that the mortality among those taking digoxin was 38.9% as compared to only 21.3% among controls. The researchers conclude that the use of digoxin in heart failure patients is associated with an adverse prognosis and suggest that beta-blockers and spironolactone may be a better choice for ameliorating the symptoms of heart failure[14].
Digoxin Toxicity & Interactions
The “therapeutic window” for digoxin is very narrow. Most patients are started on a daily dosage of 0.250 mg/day; however, this is often too little for some patients and too much for others. Very careful evaluation is required in order to find just the right dosage. Unfortunately, this is rarely done in actual practice.
Researchers at the Health Care Department in Maryland found that in the period 1985 through 1991 over 200,000 of 3.3 million digitalis users were hospitalized because of digitalis intoxication. It is ironic that digitalis is often prescribed for people who suffer from atrial fibrillation and yet, the most common manifestation of digitalis intoxication is also atrial fibrillation. Other symptoms of digitalis poisoning are nausea, vomiting, diarrhea, psychoses, and fatigue. Perhaps the most disturbing finding in the study is that in 73% of all cases the reason for prescribing the digitalis in the first place was unclear or weak. The researchers also point out that the high level of hospitalization for adverse effects of digitalis is, to a large extent, due to inadequate monitoring of patients taking the drug. It is also of concern that for the period in which the researchers uncovered data for the 200,000 hospitalizations only 577 adverse events involving digitalis were reported directly to the FDA by doctors or hospitals[15].
Other researchers have noted that digoxin is often prescribed seemingly for no good reason. Dr. Wilbert Aronow of the Mount Sinai School of Medicine found that 19% of patients admitted to a nursing home had been prescribed digoxin. A thorough medical examination and evaluation concluded that 47% of these patients should not be taking digoxin at all. Dr. Aronow also noted that 18% of the patients receiving digoxin had been misdiagnosed as having congestive heart failure even though they were in normal sinus rhythm and had a normal ejection fraction. These patients had originally presented with edema or dyspnea (laboured breathing). Digoxin therapy was safely discontinued in the 47% of the patients for whom it had been inappropriately prescribed[16].
Not only is digoxin highly toxic, but it can also interact with herbs such as Siberian ginseng and with antiarrhythmic medications such as flecainide (Tambocor), propafenone (Rythmol), and amiodarone (Cordarone)[17-19]. These drugs all increase blood levels of digoxin thus making a toxic reaction even more likely unless digoxin dosage is adjusted[18,19].
Digoxin & Atrial Fibrillation
Digoxin is still routinely prescribed for patients with atrial fibrillation even though there is no evidence that it is beneficial and growing evidence that it may actually be harmful. Digoxin does not convert atrial fibrillation to sinus rhythm[19,20]. Its ability to slow the heart rate during an atrial fibrillation episode is doubtful[21] and there is no evidence that it prevents future episodes of paroxysmal atrial fibrillation[23,24]. Dr. Rodney Falk, MD of the Boston School of Medicine sums it up, “Digoxin is probably not of value for preventing tachycardia (rapid heart beat) at the onset of paroxysmal atrial fibrillation and its use as sole agent for this indication, although widespread, has no basis”[22].
Not only is digoxin useless in the prevention and treatment of atrial fibrillation it can actually be detrimental. Dr. Philippe Coumel, MD, head of the cardiology section of the Hopital Lariboisiere in Paris says, “Not only are beta-blockers or digoxin not indicated in vagal atrial fibrillation, but they are definitely contraindicated as they tend to promote the arrhythmia and may block the action of conventional antiarrhythmic treatment”[3]. Dr. Coumel’s statement has been endorsed by the American Heart Association[5].
Researchers at the University of Michigan Medical Center go even further in their condemnation of digoxin. Their conclusion from a recent clinical trial, “The results of the present study suggest that digoxin may facilitate or promote early recurrences of atrial fibrillation after conversion to sinus rhythm not only in patients with vagotonic (vagal) atrial fibrillation, but also among the general population of patients with atrial fibrillation”[6]. It is now also clear that digoxin may not only prolong the duration of episodes, but may actually convert the paroxysmal (intermittent) form to the permanent form[6,23].
As if this is not enough, researchers have also found that digoxin can cause visual problems even at dosages normally considered safe and may significantly aggravate asthma symptoms[24,25].
Digoxin may truly be the medicine from hell and it certainly should never be used by people with lone atrial fibrillation. If a medicine is needed for the control of heart rate then calcium channel blockers such as verapamil or diltiazem or beta-blockers like atenolol or metoprolol would be a better choice.