The U.S. Food and Drug Administration warned on Tuesday that the antibiotic azithromycin, sold as Zithromax, can cause a potentially fatal irregular heart rhythm in some patients.
A study in the New England Journal of Medicine last May compared the risk of cardiovascular death from different antibacterial drugs and found that the drug, which is made by Pfizer Inc and is also sold by generic drugmakers, had a higher rate of death.
In its warning, the FDA said the drug can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal heart rhythm known as prolonged QT interval, in which the timing of the heart’s contractions becomes irregular.
The FDA said doctors should use caution when giving the popular antibiotic to patients known to have this condition or who have certain risk factors. Those who may be at risk include people with low levels of potassium or magnesium, a slower than normal heart rate, or people who take certain drugs used to treat abnormal heart rhythms, or arrhythmias. The drug could also cause problems in people with torsades de pointes, a specific, rare heart rhythm abnormality.
However, the FDA noted that other drugs in the same class as azithromycin known as macrolides also have the potential for causing QT prolongation, as do non-macrolide antibiotics, such as fluoroquinolones, and doctors need to consider all of these risks when choosing an antibiotic.
Pfizer officials were not immediately available for comment.
(Reuters)
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3 Responses
This cardiac-rhythm-disruptions “side effect” happened to me and it was a dangerous & terrifying experience.
4 points I feel are important
1) When taking a zithromax/zpac pill, this side effect is not USUALLY experienced until 6-8 hrs AFTER taking the pill. When you suddenly feel no koach, flushed, fluttery chest, can’t walk one block, or whatever your particular reaction to heart rhythm dysfunction… you may not even remember or consider the pill. Most disagreeable “reactions” to substances in my life are in under an hour. And remember the REASON you are taking the pill is because something is already wrong in the first place, making you feel lousy.
2) So it may take a few pills before you connect the scary feelings with the pill. By then you have taken how many? For various reasons, I did not take my pills at the same time of day, adding to the delay in recognizing the cause… so I took 4 days of the 5. BAD NEWS. This is a blood level drug- it lasts a long time (a fact normally considered a selling point.) It’s “half life” is several days. If you are not young & healthy, it takes even longer to get it out of your system. It can take WEEKS to leave your body. THE STUDY WAS ONLY FOR THE FIRST FIVE DAYS OF TAKING THE PILL. You are under it’s influence MUCH longer.
3) This issue is a bigger problem than they are saying. Because the study only measures fatalities, and only the first five days. It did not measure fatalities during the wearing off period. It did not measure people severely disabled during pills or “wear off”- by dangerously dysfunctional cardiac rhythms. It did not measure something more subtle I am still experiencing now- a more easily “irritable” heart, as in I am MORE bothered/triggered by caffeine, stress, physical exertion, than I had been in years. (I was even hospitalized in the past when doctors could not figure out what was “upsetting” my heart rhythms- surprise- guess what I now know? that I had been taking then?)
4) After I discovered what had been happening to me, I mentioned it to my doctors & doctor friends, my pharmacist, others. NOT ONE KNEW ABOUT THIS STUDY ON ZITHROMAX LAST MAY. My dermatologist yanked out her smart phone and looked up the info doctors use. A NEW study revealing fatalities was at the BOTTOM of the list (of MANY side effects), where busy doctors might never finish scanning to. Granted it SEEMS a RARE side effect (at least if you only count fatalities & only during the first 5 days- maybe it is NOT really so rare) But something causing fatalities SHOULD have a better warning level.
I personal DO NOT think this drug should be banned. Antibiotics are GREAT drugs which save lives. They are necessary, powerful tools, but like anything powerful, they need to be used with proper information & caution
Thank you for printing this info. Please continue to spread the word.
AvodasChesedOutofTwn – What bothers me is why were you given this in the first place? Yes, I knew about this precaution, but even though I don’t like to criticize others who practice Medicine -in this case I feel I must. PCP’s have their hands tied behing their back because if the pt. doesn’t get his/her antibiotics -they go Doc shopping. I believe let them go, but they shouldn’t get any unnecessary antibiotics. To quote one Infectious Disease expert -“Docs give out Z-paks likes it’s candy and it does nothing”.
I don’t agree with “it does nothing”, but some practitioners give it because of a side effect that it decreases lung swelling. A stupid reason to give such a potentionaly dangerous drug.
It’s time for pts. to start asking their Docs/PCP’s -is this drug really necessary? – instead of saying – I want this kind of antibiotic for what I have. I know one guy who makes a mint because he has no scruples and gives e/o what they want – so they love him.
Health- you are right in general, questioning anti biotic prescription in the first place, but I do not fault the docs here. We did discuss my not taking any. I am already VERY allergic to most, which left only two choices we knew, both of which already me cause other troubles. But antibiotics do have their place; I am not young & have multiple health issues. The occasion was having what was left of a dead, carious, broken off, deep & double rooted tooth dug out of my jaw. The crown had just fallen off revealing BAD news. I agreed with the 2 doctors & 2 dentists consulted, that even with the best dental surgeon, this was a recipe for trouble. Life is not neat. BUT if we had known about this particular side effect, I would have looked harder for other options. And others may have more choices.