How Long Does Azithromycin Stay In Your System?

For those with bacterial infections, a common antibiotic that you may be prescribed is azithromycin. There are multiple forms and doses of azithromycin, and it is crucial to follow the complete course as prescribed by your doctor.

However, it is important to remember that azithromycin lingers in your system even after taking your last dose. Continue reading to see how long azithromycin can remain in your system and what factors can affect this timeline.

Table of Contents

What Is Azithromycin?

Azithromycin is an antibiotic that belongs to the class of medications called macrolide antibiotics. It also goes by the brand name of Zithromax.

Azithromycin works against bacteria by stopping their growth. It accomplishes this by preventing bacteria from creating proteins that are essential for reproducing, which eventually kills off the bacteria.

What Is Azithromycin Used For?

Azithromycin is used to treat bacterial infections, which can include:

  • pneumonia
  • bronchitis
  • infections of the lungs, ears, skin, sinuses, reproductive organs, and throat
  • sexually transmitted diseases (STDs)

Azithromycin can also be used as a treatment or prevention of disseminated Mycobacterium avium complex (MAC) infection, which is a lung infection common in those with HIV.

Azithromycin is sometimes used to treat the following infections:

  • H. pylori infection
  • traveler’s diarrhea
  • Lyme disease
  • legionnaire’s disease
  • pertussis
  • babesiosis

In some cases, azithromycin is prescribed to prevent heart infection in those undergoing dental procedures or STDs in victims of sexual assault.

How Long Does Azithromycin Stay In Your System?

Azithromycin has a half-life of 68 hours, and it takes a drug about five half-lives before it is entirely out of your system. Based on this, azithromycin remains in your system for around 15.5 days after taking the last dose.

The long half-life of azithromycin is what makes it an appealing treatment because it means you only have to take it once a day. This is in comparison to other antibiotics, which may require two or three daily doses.

What Affects How Long Azithromycin Stays in Your System?

The estimate that azithromycin is in your system for 15.5 days is just that, an estimate. This is because many factors can affect how long it takes the body to remove all of the drug.

Quantity and Frequency

How much azithromycin you are prescribed to take will affect how long it takes for the body to remove it. For example, a 500 mg dose of azithromycin will take longer to leave the body than a 250 mg dose.

Along those same lines, the frequency that you have to take azithromycin can also affect how long it takes to remove the drug because there is more of the drug lingering from the previous doses. This means that someone who takes five doses will likely have it in their system for longer than someone who only takes three doses.

Metabolic Rate

Your metabolic rate is how fast your body can break down what has been consumed. In the case of food, this then equates to the amount of energy it expends or the number of calories it burns.

For antibiotics, a higher metabolic rate equates to a shorter duration of the medication in your body. This is because your body is breaking down the antibiotic and removing it from your body faster than those with a lower metabolic rate.

Body Mass

Generally, the more you weigh and the bigger you are, the longer a drug will remain in your system.


Those who are older often have a drug in their system for a longer amount of time. This may be because their organ systems cannot clear out the drug as efficiently as a younger body can.


In terms of overall health, those with poorer health are often unable to clear out a drug as fast, increasing the amount of time it lingers in their system.

How to Correctly Use Azithromycin?

Azithromycin comes in three forms, a tablet, liquid, or extended-release liquid. The tablets and liquid suspension are typically taken once a day for 1-5 days and can be taken with or without food. When used to prevent disseminated MAC infection, the tablets are often taken once a week.

The extended-release liquid is taken as a one-time dose on an empty stomach (one hour before a meal or two hours after). When taking azithromycin in a liquid form, be sure to shake the suspension well before taking it to mix the medication.

It is crucial to take azithromycin as prescribed by your doctor and to take the complete course of the antibiotic to ensure the infection is fully treated.

What Are the Common Side Effects of Azithromycin?

The most common side effects of azithromycin include stomach upset with symptoms such as nausea, vomiting, diarrhea, and stomach pain. Azithromycin may also cause headaches.

When to See a Doctor?

There may be some severe side effects of azithromycin, including:

  • dizziness
  • fast, irregular, or pounding heartbeat
  • fainting
  • blisters or peeling skin
  • rash
  • fever
  • hives
  • wheezing or difficulty breathing
  • itching
  • redness and swelling of the skin
  • pus-filled, blister-like sores
  • hoarseness
  • yellowing of the eyes or skin
  • unusual bruising or bleeding
  • loss of appetite
  • dark-colored urine
  • pink and swollen eyes
  • upper right abdominal pain

If you are taking azithromycin and experience any of the above symptoms, it is crucial to speak to a doctor immediately or seek emergency medical services.

Get Help From an Online Doctor!

If you are concerned about continuing other medications or drinking alcohol following an azithromycin prescription, an online doctor can be a great resource to discuss if it is safe to resume these activities or when you should wait.

For those with an infection, online doctors such as those on DrHouse can prescribe antibiotics such as azithromycin online, making it easier than ever to get the medicine you need to feel better.

In Conclusion

Azithromycin is an antibiotic used against bacterial infections to stop bacteria growth. It may also be used as a preventive against disseminated MAC infection or as a treatment against some gastrointestinal infections.

Azithromycin has a long half-life of around 68 hours. This means that it only needs to be taken once a day, but it also means that azithromycin remains in your system for about 15.5 days following your last dose. Certain factors can increase or decrease this estimate.

For those who need an antibiotic prescription, an online doctor can prescribe medication virtually and discuss what you should avoid as azithromycin treats the infection and leaves your system.


Content on the DrHouse website is written by our medical content team and reviewed by qualified MDs, PhDs, NPs, and PharmDs. We follow strict content creation guidelines to ensure accurate medical information. However, this content is for informational purposes only and not a substitute for professional medical advice, diagnosis, or treatment. For more information read our medical disclaimer.

Always consult with your physician or other qualified health providers about medical concerns. Never disregard professional medical advice or delay seeking it based on what you read on this website.

If you are experiencing high fever (>103F/39.4C), shortness of breath, difficulty breathing, chest pain, heart palpitations, abnormal bruising, abnormal bleeding, extreme fatigue, dizziness, new weakness or paralysis, difficulty with speech, confusion, extreme pain in any body part, or inability to remain hydrated or keep down fluids or feel you may have any other life-threatening condition, please go to the emergency department or call 911 immediately.



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