What is Azithromycin Used For?

Published March 24th, 2020 by Corey Riley
Fact Checked by
Chris Riley
Updated Date: Jun 30th, 2022

The number of hospital admissions due to acute bacterial infections is on the rise in the United States. 

Infections caused by bacteria can affect any part of the body, with more common ones affecting the skin, upper respiratory tract or urinary tract.

These infections are all caused by different bacterial species.

For example, some of the better-known bacterial infections, like Strep throat, are caused by the Streptococcus group of bacteria. Other relatively common bacterial infections like sinus infections can be caused by a variety of bacterial species. In all cases, bacterial infections are treated with antibiotics that halt the growth of bacteria and prevent them from growing inside our body and making us sick. 

In the United States alone, antibiotics are prescribed at a higher rate compared to other countries, with an estimated 270 million antibiotic prescriptions written in 2015. By international standards, this is a high rate of antibiotic prescriptions per year.

Approximately 30 percent of all antibiotic prescriptions in an outpatient setting are prescribed for asthma, allergies, or a cold. 

The effectiveness of antibiotics in treating the illness depends on whether the antibiotic prescribed can efficiently kill the specific bacteria that cause the illness. It is important to note that antibiotics do not work for illnesses caused by a virus, like the common cold or flu, or for illnesses causes by fungal species. Antibiotics selectively kill only bacteria and do not harm human cells at therapeutic doses either.

Many antibiotics that belong to different classes based on how they work are available for bacterial infections. Some of the more commonly known ones, like penicillin, have been around for more than ninety years now. More recently discovered antibiotics have also proven to be very successful in treating bacterial infections.

The Macrolide class of antibiotics is one of these. The Macrolides were first discovered in nature in 1990 and they were further optimized to develop what is the most commonly prescribed antibiotic in the United States today- Azithromycin.

In fact, annually Azithromycin is one of the most commonly prescribed drugs overall in the United States. 

Understanding Azithromycin

What is Azithromycin?

Azithromycin is a broad-spectrum antibiotic, which means that it is effective against a wide-range of bacteria.

Azithromycin is considered to be superior to other macrolide antibiotics like Erythromycin and Clarithromycin due to its increased ability to penetrate tissues and its decreased sensitivity to stomach acid.

Due to this reason, Azithromycin can be absorbed well on an empty stomach and can be taken without food. Azithromycin is usually given as oral tablets, but can also be administered intravenously for acute conditions.

It works by blocking the production of bacterial proteins that are needed for their survival. When these proteins cannot be made, the bacterial growth is halted and the infection is cleared.

There are many indications for which Azithromycin is prescribed. The main uses are summarized here: 

Upper Respiratory Tract Infections 

Respiratory Tract infections are usually caused by viruses leading to the ‘common cold’.

These are not treatable by antibiotics like Azithromycin. However, when they are caused by bacteria, antibiotics can be effective in preventing the bacteria from multiplying and clearing the infection. Azithromycin is very commonly prescribed for upper respiratory tract infections due to bacterial causes.

What is an upper respiratory tract infection? Infections of the throat (laryngitis), trachea (tracheitis), or bronchi, the airways that lead to the lungs (bronchitis) are all collectively grouped under upper respiratory tract infections.

Common symptoms of an upper respiratory tract infection include a runny nose, sneezing, congestion, and discharge from the nose that is clear at first but progresses to a deep yellow or green over the course of a few days. 

This may also be accompanied by a cough or mild fever. An important consideration is that most upper respiratory tract infections resolve themselves in healthy individuals and do not need treatment with antibiotics. If the infection spreads to other areas like the sinuses, lungs, or ears, then usually antibiotics are prescribed.

Azithromycin can treat the infection and kill the bacterial source of the infection. Azithromycin is also prescribed for infections of the surrounding areas like tonsillitis, throat infections (pharyngitis) and sinuses (sinusitis)

Ear Infections

Ear infections can occur in the ear canal (otitis externa) or in the space behind the eardrum called the middle ear (acute otitis media).

The middle ear space normally contains air, but can become filled with mucus due to a cold.

The mucus can then become infected with bacteria or virus causing an ear infection. Acute otitis media can be treated with Azithromycin when it is caused by bacteria.

Common symptoms of an ear infection are an earache and high fever. Middle ear infections most commonly affect children. As early as 2000, a multi-center clinical trial conducted by Pfizer (that markets Azithromycin as the brand Zithromax), found that a single dose of Azithromycin was as clinically effective as a 10-day course of amoxicillin administered twice a day in clearing acute otitis media in children.

Even though Azithromycin is just as effective for acute otitis media, amoxicillin is still often prescribed first unless a patient has a penicillin allergy.  

Community-Acquired Pneumonia

Pneumonia that develops outside of a hospital setting is called ‘community-acquired pneumonia’.

Typical bacterial species that cause this are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Atypical bacteria like Mycoplasma pneumoniae and Legionella species can also cause this. It can also be caused by a virus. A few symptoms of pneumonia are fever, cough, high sputum production, chest pain and dyspnea.

A chest X-ray can confirm diagnosis of pneumonia.

Current guidelines for treatment of community-acquired pneumonia recommend treatment with a macrolide antibiotic, like Azithromycin, along with another antibiotic belonging to the fluoroquinolone class of antibiotics. Without prompt and proper treatment, pneumonia can be a serious illness that is sometimes fatal in older patients with pre-existing illnesses. 

Traveler’s Diarrhea

Acute diarrhea is a very common condition that affects travelers due to ingestion of food and water contaminated with fecal matter that is a source of bacteria like E. coli, Campylobacter, Salmonella, and Shigella. One study found that an estimated 46% of Americans that travel to developing countries develop acute diarrhea.

Symptoms present as bloody stools, fever, vomiting, and nausea. Several antibiotics are recommended for treatment of Traveler’s Diarrhea, and Azithromycin is one of the main ones.

In areas where bacteria that are resistant to other classes of antibiotics like the quinolones are present, Azithromycin is the first choice- antibiotic for treatment. A single dose of Azithromycin at 1000 mg or 500 mg for one to three days is the standard recommended treatment for Traveler’s Diarrhea. 

Skin Infections 

Skin infections can occur due to bacterial colonization of the skin and surrounding tissues.

This is usually caused by bacteria like Staphylococcus aureus, Streptococcus agalactiae, or Streptococcus pyogenes. Azithromycin can be prescribed for some skin infections depending on the species and severity of the infection. 

Strep Throat

Strep throat is an infection of the throat and tonsils that is caused by bacteria. Symptoms of Strep throat include a sore throat, fever and swollen glands.

Antibiotic treatment of strep throat gets rid of the bacterial infection and prevents a more serious condition, like rheumatic fever, from arising. The first-line treatment for Strep throat is usually penicillin-based antibiotics, like Amoxicillin.

However, Azithromycin is prescribed for people who are allergic to penicillin, or for any other reason based on your personal history. Azithromycin can be prescribed as a ‘Z-pack’. 

Sexually Transmitted Diseases (Gonorrhea and Chlamydia)

Azithromycin is the recommended antibiotic treatment for several sexually transmitted diseases (STDs) like Gonorrhea, Chlamydia, and Syphilis.

In all cases, Azithromycin is taken in combination with another antibiotic to ensure complete eradication of the infection.

If left untreated, STDs can cause serious health complications and even become life threatening. For example, untreated gonorrhea can lead to Pelvic Inflammatory disease in women or infection of the testes in men.

Both complications can lead to infertility. The Center for Disease Control (CDC) recommends treatment of gonorrhea with a combination of Azithromycin and Ceftriaxone. 

Immuno-modulatory Uses

Additionally, some anti-inflammatory uses of the macrolide antibiotics, including Azithromycin, that are not related to their use for bacterial infections have been documented.

Research has shown that macrolides can also inhibit the production of molecules in the body that promote inflammation, called cytokines. Due to this, they can be used in chronic inflammatory diseases like Inflammatory Bowel Disease or potentially Rheumatoid Arthritis. 

How to save on Azithromycin

If you are prescribed Azithromycin by your doctor for any of these indications listed above or otherwise, it is extremely important to take the complete dose prescribed even if your symptoms resolve before your finish your course.

Not taking antibiotics prescribed for the entire course can lead to antibiotic-resistant bacterial infections that cause more complications since there are limited treatment options available for resistant-infections. 

The cost of prescription drugs, like Azithromycin, can be a concern for patients that take the drug frequently.

Where can I buy Azithromycin?

If you are prescribed Azithromycin or its brand-version, Zithromax, you can pick it up from any pharmacy by taking your prescription in with you.

Health insurance should help you save on the cost of this drug, but you can get additional savings on this antibiotic with coupons for Azithromycin available from USA Rx.

If you take more than one prescription medication, you can also sign up for a free pharmacy discount card also available through USA Rx that can be used on any FDA-approved drug.

Signing up for this card takes only a few minutes and can be done online by simply entering your name and contact information.

The discount card can be printed from the convenience of your home and presented at your pharmacy when filling a prescription to help you save more on purchasing Azithromycin and get you on your way to feeling better quickly. 

References, Studies and Sources: 

Azithromycin - Wikipedia

Medline - Azithromycin