What Happens If You Take Your Z-Pak (Azithromycin) Out Of Order?

In our latest question and answer, the pharmacist discusses what happens if you take your Z-Pak out of order.


What happens if you take azithromycin Z-Pack out of order? I mixed the pills up in the blister pack somehow.

Asked by Miley On Sep 29, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Sep 29, 2022
Last updated Sep 29, 2022

Key points

  • A Z-Pak contains 6 tablets for a 5-day course of therapy. Each tablet contains 250mg of azithromycin.
  • It is important to take 500mg (two tablets) as your first dose since it acts as a 'loading dose', and then 250mg (one tablet) daily thereafter.
  • Every tablet of a Z-Pak contains 250mg, so it doesn't matter if they are taken in order. What is important is that you take 500mg for your first dose, then 250mg daily thereafter.


The Z-Pak contains six 250mg azithromycin tablets and is dosed for 5 consecutive days. The directions are as follows:

  • Take two tablets (500mg) by mouth on day one.
  • Take one tablet (250mg) by mouth on days two through five.

It doesn't matter if you take the azithromycin tablets contained in the Z-Pak out of order as they are all the same strength, 250mg. It does matter, however, that you take two tablets (500mg) as your first dose. If you don't, there is a chance that drug concentrations will not be high enough to completely cure your infection.

The Day One Loading Dose Is Important

The day one dose of the Z-Pak (500mg) is considered a loading dose and is used to achieve high drug concentrations in the body. The next 4 days' doses, all one tablet of 250mg, are used to maintain those high drug levels. 

Azithromycin is able to be dosed only once a day as it has a long half-life (around 68 hours), and one dose stays in the body for a considerable amount of time.

The 500 mg day one "loading dose" produces appropriately high levels of the drug in your body, which is then maintained with the 250 mg daily doses for the next four days. If you do not take a loading dose, the concentrations of azithromycin may not reach high enough levels, which could cause your bacterial infection not to resolve.

If did not take two tablets of azithromycin as your first dose, speak with your doctor to discuss your options. If you simply took the tablets in your Z-Pak out of order but still took two tablets for your first dose, it is of no consequence as they all contain 250mg.

Final Words

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About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 11 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Feel free to send him an email at Hello@HelloPharmacist.com! You can also connect with Dr. Brian Staiger on LinkedIn.

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