Tuesday's warning about Zithromax causing heart irregularities reportedly came after the FDA completed its own review of a New England Journal of Medicine article published in May 2012 and after reviewing additional data provided by Pfizer. I have already voiced my concerns over the way this study was conducted in the first place since the data upon which the authors' risk estimates were made were shoddy at best. Still, it is quite obvious to those of us in the business of cardiac arrhythmias that Zithromax, when combined with other medications likely to prolong QT interval or given to sick patients, could increase one's arrhythmic risk.
But we should look closer at the FDA's new Drug Safety Communication on Zithromax which says: "Health care professionals should consider the risk of torsades de pointes and fatal heart rhythms with azithromycin when considering treatment options for patients who are already at risk for cardiovascular events."
Gee, who knew?
If we probe deeper, we find the FDA recommends caution in prescribing antibiotics in patients likely to develop life-threatening cardiac arrhythmias like those with advanced age who are hospitalized, have low potassium or magnesium blood levels, or have slow heart rhythms. The truth be known, each one of these conditions in and of themselves increases the risk of QT prolongation and makes them more susceptable to cardiac arrhythmias irrespective of the drug admininstered.
So how helpful was the FDA's warning on Zithromax to America's doctors?
Perhaps we should add that warning to every drug out there, eh?