Digoxin poisons all Na+/K+ pumps, INCREASING risk of AF.

Digoxin [en.wikipedia.org]

Excerpts:

Pharmacokinetic properties

Quinidine, verapamil, and amiodarone increases plasma levels of digoxin (by displacing tissue binding sites and depressing renal digoxin clearance) so plasma digoxin must be monitored carefully. Researchers at Yale University looked at data from an earlier study to see if digoxin affected men and women differently. That study determined that digoxin, which has been used for centuries and makes the heart contract more forcefully, did not reduce deaths overall but did result in less hospitalization. Researcher Dr. Harlan Krumholz said they were surprised to find that women in the study who took digoxin died more frequently (33%) than women who took a placebo pill (29%). They calculated that digoxin increased the risk of death in women by 23%.

Adverse effects

The occurrence of adverse drug reactions is common, owing to its narrow therapeutic index (the margin between effectiveness and toxicity). Adverse effects are ... more common in patients with low potassium levels (hypokalemia), since digoxin normally competes with K+ ions for the same binding site on the Na+/K+ ATPase pump.

Common adverse effects (≥1% of patients) include: loss of appetite, nausea, vomiting and diarrhea as the gastrointestinal motility increase. Other common effects are blurred vision, visual disturbances (yellow-green halos and problems with color perception), confusion, drowsiness, dizziness, insomnia, nightmares, agitation, and depression, as well as a higher acute sense of sensual activities.[8] Less frequent adverse effects (0.1%–1%) include: acute psychosis, delirium, amnesia, convulsions, shortened QRS complex, atrial or ventricular extrasystoles, paroxysmal atrial tachycardia with AV block, ventricular tachycardia or fibrillation, and heart block[7] Rarely, digoxin has been shown to cause thrombocytopenia. Gynaecomastia (enlargement of breast tissue) is mentioned in many textbooks as a side-effect – thought to be due to the estrogen-like steroid moiety of the digoxin molecule[9] but when systematically sought, the evidence for this is equivocal.[10] The pharmacological actions of digoxin usually results in electrocardiogram (ECG) changes, including ST depression or T wave inversion, which do not indicate toxicity. PR interval prolongation, however, may be a sign of digoxin toxicity. Additionally, increased intracellular Ca2+ may cause a type of arrhythmia called bigeminy (coupled beats), eventually ventricular tachycardia or fibrillation. The combination of increased (atrial) arrhythmogenesis and inhibited atrio-ventricular conduction (for example paroxysmal atrial tachycardia with A-V block) is said to be pathognomonic (i.e. diagnostic) of digoxin toxicity.[11]

An often described but rarely seen adverse effect of digoxin is a disturbance of colour vision (mostly yellow and green colour) called xanthopsia. It has been proposed that the painter Vincent van Gogh's "Yellow Period" may have somehow been influenced by concurrent digitalis therapy. Other oculotoxic effects of digoxin include generalized blurry vision as well as seeing a "halo" around each point of light.[12] The latter effect can also be seen in van Gogh's Starry Night. Evidence of van Gogh's digoxin use is supported by multiple self portraits that include the foxglove plant, from which digoxin is obtained. (E.g. Portrait of Dr. Gachet)

Digoxin plasma concentrations may increase while on antimalarial medication hydroxychloroquine (based on two case reports from 1982).[13]

In overdose, the usual supportive measures are needed. If arrhythmias prove troublesome, or malignant hyperkalaemia occurs (inexorably rising potassium level due to paralysis of the cell membrane bound ATPase-dependent Na/K pumps), the specific antidote is antidigoxin (antibody fragments against digoxin, trade names of Digibind and Digifab).[14] Toxicity can also be treated with higher than normal doses of potassium. Digoxin is not removed by hemo or peritoneal dialysis with enough effectiveness to treat toxicity.

Digoxin has potentially dangerous interactions with verapamil,[15] amiodarone, erythromycin, and epinephrine (as would be injected with a local anesthetic).


Mechanism of action

Digoxin binds to a site on the extracellular aspect of the α-subunit of the Na+/K+ ATPase pump in the membranes of heart cells (myocytes) and decreases its function. This causes an increase in the level of sodium ions in the myocytes, which leads to a rise in the level of intracellular calcium ions. This occurs because the sodium/calcium exchanger on the plasma membrane depends on a constant inward sodium gradient to pump out calcium. Digoxin decreases sodium concentration gradient and the subsequent calcium outflow, thus raising the calcium concentration in myocardiocytes and pacemaker cells.

Increased intracellular calcium lengthens Phase 4 and Phase 0 of the cardiac action potential, which leads to a decrease in heart rate.[16] Increased amounts of Ca2+ also leads to increased storage of calcium in the sarcoplasmic reticulum, causing a corresponding increase in the release of calcium during each action potential. This leads to increased contractility, the force of contraction, of the heart.

There is also evidence that digoxin increases vagal activity, thereby decreasing heart rate by slowing depolarization of pacemaker cells in the AV node.[17] This negative chronotropic effect would therefore be synergistic with the direct effect on cardiac pacemaker cells. Digoxin is used widely in the treatment of various arrhythmias.



Edited 1 time(s). Last edit at 02/17/2012 09:56PM by Erling.

When i first got afib in oct '99 at age 58, i was prescribed digoxin and took it for maybe 6 months. I had no ability to climb stairs, out of breath after half a flight. If i laid my head down for a minute during the day i went right to sleep no matter how long i had slept the night before. I had no initiative,no energy. I thought old age had caught up with me. One month my scanty money ran out before i could get my prescription for digoxin filled. It only cost $9.00,but i did not have it. I went to taking it every other day, trying to make it last. I soon found that youth returned on the days i did not take my digoxin pill, and back to decrepitude on the days i did take it. It was too strong a clue to be ignored, and i stopped refilling the prescription altogether. I caught a lot of flack from whatever medic i encountered, but i never went back to the digoxin and eventually everybody but me forgot about it. I saw doctors from time to time but none of them ever prescribed digoxin to me again. I thought i must be some sort of a freak not to be able to take this medicine. I was the only person i knew who had this weird afib affliction,not to mention how incredulous was the reaction from any doctor to whom i tried to explain why i had stopped taking this wellknown, much-prescribed medication. These doctors none of them could explain to me why i had gotten this afib either,but at least they stopped trying to get me to take digoxin. Until i found this forum i just thought i had a strange reaction to the medication. It seemed to me in my ignorance that this was similar to not being able to take penicillin [i was allergic to penicillin].

PeggyM

Peggy – Thanks for your excellent testimonial and more support showing Digoxin is “The Medicine from Hell” as Hans offered in his report.

Early in my AF journey, the mention of Digoxin was made by an otherwise really helpful cardiologist. Since I had already discovered this forum and had read the warnings about Digoxin, I just smiled and said that most likely, I’d not be wanting to consider taking that drug. Eventually, flecainide was prescribed.

When I read the data that Erling has offered here, I become furious all over again that doctors insist on using this ‘old standby’ and it truly makes me wonder if they ever really took the time to understand how the drug functions.

Thanks Erling for this reminder.

Jackie

You guys are absolutely correct. Digoxin is the first drug most emergency rooms will try pumping into you if you check in with afib. It shows you how far out of touch a lot of Drs. are. I wonder how many of them actually look at new data and information. The medical field has new breakthroughs every day with regards to treatment and medication, but so many of these Drs. knowledge dates back to the 1950's. Pretty sad.
Lou

Early-ish in my Afib career, and in my pre-Forum days, I was prescribed both Digoxin and Amiodorone. Being, even then, a very reluctant medication taker, I looked them both up and decided their side-effects sounded terrifying, so I refused on the grounds that a responsible MD would not make such awful recommendations! After reading Erling's post, I am even more disgusted! Thank you, Erling! What a good reminder that we have to be very savvy consumers.

Louise

Yep, and aint it great? My very first AF had me on digoxin at once, even though the episode converted in 3 hours, long before the Board Certified Cardiologist even saw me. He said I should be ‘digitized’ (?). .

Michael's mother, 84 (see below) with new onset (the first) AF was cardioverted and did well in NSR for three weeks. When AF returned, she was put on digoxin, Amiodarone, a beta blocker, an ACE inhibitor, Pradaxa, as well as Lasix, apparently without benefit. When she's in AF she loses energy, has trouble breathing, therefor the EP recommended replacing her God-given AV node with a battery operated pacemaker!!

Knowing exactly what digoxin does by poisoning all Na/K pumps in all 70 trillion cells of the body, not just those of the heart, seems essential. About the totality of adverse "side effects" from the rest of that ungodly cocktail I have no idea, and won’t spend time finding out. I don’t know whether to cry or laugh or climb the walls in outrage. To paraphrase the question that got Richard ‘Tricky Dick’ Nixon to resign: What do her doctors not know and when did they choose to not know it? Or do they? You can be sure that BigPharma’s / BigMedicine’s cash registers are ringing ca-ching! ca-ching! ca-ching !

Erling.

Erling, I appreciate your concern and posts about basic physiology. As part of my research and interest in the topic, I have ran across a new novel form of Mg++ that was designed to cross the blood brain barrier. See links:

[www.magtein.com]
[en.wikipedia.org]

Perhaps you are aware of it. I have contacted the PhD who is in charge of the commercialization of the product to ask what she knows about cardiac tissue levels with the formulation. When she found out I was not a research PhD she did not get back with me. At any rate I did not see it in the store. If this novel form of Mg can cross the blood brain barrier, can it get into the heart and other tissues easier as well? I look forward to your thoughts.

Michael

Michael - while the new form of magnesium looks very useful for brain health, we absolutely know that the Albion amino acid chelated form (Magnesium glycinate) is highly efficient for absorption since it is not broken down in the stomach. Why not go with what we know for sure works well and not lose time unless that PhD you contacted can give you reports showing it works equally efficiently for both heart and brain?

Please post what you do learn, though, because this might be a very important addition to our armamentarium.

Best wishes to both you and your mother.
Jackie

Just read this thread and hated digoxin before but now despise and loathe the junk. My brother has been on it for almost two yrs. and has all the issues just read about as far as aging like mad and no appetite (He is a scarecrow!). The question is: WHAT DOES HE TAKE? He is not an afibber...I am...he has a congestive heart problem and it almost killed him a couple of yrs. back. His pulse was something like 47, and I am sure the docs felt they had to give something to create a more forceful heartbeat. Somebody got a suggestion for us? I finally got him off the statins. Oh, the words I could use to describe my feelings about those!! Surely all these docs cannot be such blithering idiots. Sorry, I am going into histrionics and to no avail.

Now then, there is myself as well. I am putting a brave face on things but the truth is that recently I find that my heart is in afib or palps most of the night or even in the day if I slump in my chair (vagal). I may need to change to the mg. glycinate which I hated but am now taking the mg. citrate. It is possible it contributes. Taking two tablets at H.S. I also use klonopin at low dose which I do not raise as I know the tolerance increases with the raises.

What are the dietary recommendations for afibbers? I just drank some relaxing tea and it is effective, so I better hit the sack. Much obliged for any suggestions. jaydee zzzzzz