How safe is a Z-pak?

Text message: “John, This cough and congestion is killing me. It’s turning thick and green. Can you write me a Z-pak? It always works for me.” If you write a blog on medical decision-making and heart rhythm matters, it seems an incredible omission not to opine on the FDA warning concerning the commonly used antibiotic azithromycin (the drug in a Z-Pak). Quoting directly from the FDA warning: [Azithromycin] can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm. Should we say this more clearly: that simple antibiotic you are taking for a minor infection could be lethal! This is something, isn’t it? In the following paragraphs, I will present the facts, describe the study that led to warning and then offer my bottom-line take home. It all started in May 2012 when a group of researchers from Vanderbilt published this widely publicized and controversial study in the New England Journal of Medicine. As background, the research team knew that azithromycin, which belongs to a class of antibiotics called macrolides, has the propensity to prolong the QT interval. The QT interval is the time from the onset of heart muscle activation to completion of relaxation. It’s an important interval because excessive lengthening of the QT can lead to lethal cardiac arrhythmia, which we give the French name torsades de pointes (twisting of the points.) An individual’s susceptibility to QT prolongation is highly he...
Source: Dr John M - Category: Cardiology Authors: Source Type: blogs