Is Azithromycin Still Working After The Last Dose?

Hi Chico and thanks for reaching out to us. 

Azithromycin is a very commonly used antibiotic to treat a variety of infections such as sinus infections, ear infections, upper respiratory infections, and several other common bacterial infections.

One of the big advantages of using azithromycin is the ease of dosing. Many antibiotics are dosed three or four times daily. Azithromycin is always just once a day. This is due to its long half-life.

The 'half-life', in this sense, is the amount of time that it takes for your body to metabolize half of the medication and remove it from your body. The half-life for adults is variable, but it averages 68 hours for azithromycin.

What this means is that if you were to take a single dose of azithromycin, after 68 hours half of the initial dose would still be in your system.

The most common form of azithromycin is the 5-day Z-Pack. You take 2 tablets on day 1, 1 tablet on days 2-5, and then stop.

Due to the long half-life of azithromycin, it keeps working to treat bacterial infections for another 5 days or so after your last dose, simply due to the fact that you’ve been taking it regularly for the last 5 days. 

So, if it doesn't seem like your infection is getting better after 5 days of being on azithromycin, that's generally okay...it is still working, and you should see an improvement soon. If you still see no improvement a few days after your last dose, be sure to reach out to your doctor.

I hope this helps! Feel free to write us again in the future.