Doxycycline vs. Azithromycin

Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson reviews the fundamentals of two antibiotics called doxycycline and azithromycin and compares their effectiveness in treating specific conditions. It also discusses some of the side effects and potential interactions of each antibiotic.

Drugs of Choice

When reaching for an antibiotic, a drug that kills or inhibits the growth of bacteria, a doctor has a very broad range of options to choose from. The appropriate choice depends on exactly what condition is at hand, the patient's general health status, and the antibiotic's effectiveness and potential for side effects.

Two of the many options at a doctor's disposal when balancing these considerations are antibiotics called doxycycline and azithromycin. In this lesson, you're going to learn about the fundamentals of each medication and, as a result, their major similarities and differences.

Let's get to it!



Doxycycline is a bacteriostatic antibiotic. Nope, it has nothing to do with shocking bacteria with a static charge of electricity. Although wouldn't that be cool? Instead, a bacteriostat is an antibiotic that inhibits the reproduction of bacteria. Doxycycline does so by preventing bacteria from synthesizing proteins.

Doxycycline is sold under a variety of brand names, including Vibramycin, Monodox, and Atridox.

It's used to treat numerous types of diseases, including:

  • Sexually transmitted infections, like gonorrhea and chlamydia
  • Urinary tract infections
  • Intestinal infections
  • Periodontitis, often called gum disease

And some potential side effects of this medication include:

  • Headache
  • Flu-like symptoms
  • Nausea


Like doxycycline, azithromycin is a bacteriostatic antibiotic and works in much the same way. The generic drug name may not ring a bell, but it's commonly sold as Zithromax and Zmax.

Azithromycin is used for many of the same problems doxycycline is; for example, it can be used to treat gonorrhea. Other problems azithromycin is used for include:

  • Skin infections
  • Respiratory infections
  • Ear infections

People who have traveled abroad recently may have even been given this medication to help treat traveler's diarrhea as well.

Some important side-effects to keep in mind when considering azithromycin include:

  • Diarrhea -- ironic, right? Given the fact that it can help prevent it as well.
  • Nausea and vomiting
  • Abdominal pain



Doxycycline and azithromycin are both almost always taken orally. However, both of them also come in formulations designed to be given intravenously.


Both doxycycline and azithromycin can be used to treat similar diseases. For example, both are recommended as excellent choices for the treatment of chlamydia. There is a caveat, however. While their effect is almost the same, it appears that doxycycline is the better choice if the administration and use of the medication can be monitored by a medical professional. In cases where this isn't the case, there is almost no difference in their effect. Exactly why is unclear but it may have something to do with azithromycin's side effects or simply the limitations of the design of the study that noted this difference.

When it comes to the treatment of acne, doxycycline and azithromycin are seen as being equally effective. Again, there is a caveat. In patients over the age of 18 it looks like doxycycline is more effective at treating acne. Another skin condition, rosacea, is treated equally well by either azithromycin or doxycycline.

Doxycycline is also well-known for treating Lyme disease, a disorder transmitted via ticks, one that can lead to everything from a rash to joint pain. When there is a rash involved, then doxycycline and azithromycin are both seen as being equally effective. Otherwise, doxycycline is usually the treatment agent of choice.

Both drugs have been used to treat pelvic inflammatory disease as well. This disease refers to the infection of a woman's reproductive structures. When combined with an antibiotic called ceftriaxone, azithromycin is at least as good as, if not better, than ceftriaxone combined with doxycycline.

Side Effects & Safety

Many of the most expected side-effects of these medications are quite similar. For example, nausea and diarrhea are both potential (and relatively common) side effects for these medications.

Doxycycline is rarely recommended for children under 8, or in pregnant women, as it is far more likely to lead to tooth discoloration and skeletal growth defects in the child. Similarly, it's not recommended to take this medication while breastfeeding.

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