Written by 11:58 pm Prescription Drugs

Is Zithromax Safe Anymore? I think so…

Well, if you’ve been tuned into Pharma news today, you have undoubtedly heard about some warning regarding the use of Zithromax and an increased risk of cardiovascular events (that’s a health care euphemism for death by heart attack or similar baddy). 

Twitter streams went wild spreading the warning.  News sites carried headlines – doing their duty to sound the alarm.  I believe I saw several children running through the streets, dumping out their Zithromax suspensions – mom’s chasing them in horror.

A small sampling of the headlines I read:

  • FDA: Z-Pack Antibiotics May Lead To Fatal Heart Issues
  • Pfizer’s (PFE) Zithromax Can Cause Abnormal Heart Rhythms
  • New Heart Warning for Popular Z-Pak Antibiotics
  • FDA says Zithromax can cause fatal irregular heart rhythm
  • Zithromax antibiotic can cause fatal irregular heart rhythm

Pfizer, by the way, has already come out with a consoling statement to try and address the news.

So, what’s the deal?  Should we, as pharmacists, just return all our Azithromycin products immediately to McKesson and hope we can get some credit?  Should patients stop their Z-pack mid-course, and immediately head to the ER for and EKG?

Let’s try to stay calm and see what this is all about.

First, for those NOT inside the pharma-world, let me just explain what Zithromax (generic name azithromycin) is.  You may know it as a Z-Pak, or possibly a Tri-pak.  It is an antibiotic that belongs to a family of medications known as “macrolides” (a family that also includes erythromycin and clarithromycin).  It is typically used to treat various upper respiratory tract infections such as a sinus infection, strep throat or ear infections.  It may also be used under certain circumstances to treat pneumonia.  It is the one that you typically take for 5 days, using a double dose on the first day.  You remember.  It comes in suspensions and tablets, or as injection for in-patient situations.


Second, lets try and shed some fair and reasonable light on the data.  What are the numbers?  What are the facts?  The warnings originally arose from a New England Journal of Medicine (NEJM) article back in May of 2012. 

Here is the original article: http://www.nejm.org/doi/full/10.1056/NEJMoa1003833?query=emergency-medicine

Note the facts in the “results” section please: 

  • 47 deaths per 1,000,000 courses of Zithromax for low-risk patients.
  • 245 deaths per 1,000,000 courses of Zithromax for higher-risk patients.


Third, let’s draw some conclusions.  Using the HIGH RISK patient as a gauge (just to be more than fair), it appears I would have to dispense 4,081 courses of zithromax to result in the death of 1 patient.  Put this in perspective.   If I dispense 1 Zpak to a HIGH RISK  patient EVERY SINGLE day (taking NO DAYS OFF…ugghh..this is going to be hard) then it will be May 14, 2024 before 1 patient dies from this treatment.  Presumably these patients had a more severe infection, for which amoxicillin was not really appropriate.  I think we can be reasonably certain that the consequences of NOT prescribing this antibiotic will result in significantly more deaths and more disease.


In conclusion, our FDA reviewed the data (finally) and has decided to increase the warning associated with Zithromax in patients who may be at higher risk.  Fine.  Not entirely unreasonable.  But let’s not lose perspective here.  The risk is still incredibly small, and really cannot be compared to the risk of non-treatment for serious infections from this data.  Other antibiotics may pose similar risks.  And for those concerned about the residual effect (i.e. you took Zithromax last year…are you in danger?) the answer is no.  From the study authors: “The increased risk of cardiovascular death during the usual 5-day course of azithromycin therapy did not persist after the course of therapy ended

So, finish your Z-pak.  Don’t return all your Azithromycin to McKesson just yet.  And tell your toddler who dumped his antibiotic down the drain while screaming “POISON!!” that you are going to need a refill.

Last modified: April 17, 2023