Pack of Zithromax medication for chlamydia against a pink background

Zithromax® for Chlamydia: What You Need to Know

Written on September 21, 2023 by Lori Mulligan, MPH. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

You just found out that you may have been exposed to chlamydia, a sexually transmitted disease (STD)… Now what?

First, let’s review transmission and its symptoms before we talk about using the antibiotic Zithromax® for chlamydia.


Chlamydia is an STD that you can get from having sex with a person who already has it. You can get chlamydia from having any kind of sex: oral, vaginal, or anal.


Men may have:

  • No symptoms at all
  • Discharge (drip) from your penis
  • Pain and swelling in your testicles
  • Pain or discomfort when urinating (peeing)

Women may have:

  • No symptoms at all
  • Change in your usual vaginal discharge
  • Pain during sex
  • Bleeding or spotting between periods or after sex
  • Pain in lower belly or pelvis
  • Pain when urinating (peeing)

Zithromax® for Treatment

Zithromax®, also known as azithromycin, is considered a very safe medicine, but there are some precautions to follow, such as:

  • You are female and have lower belly pain, pain during sex, vomiting, or fever.
  • You are male and have pain or swelling in the testicles or fever.
  • You have one or more painful, swollen joints.
  • You have ever had a bad reaction, rash, breathing problems, or allergic reaction after taking any kind of antibiotic.
  • You have a serious long-term illness, like kidney, heart, or liver disease, or HIV infection.
  • You are currently taking another prescription medicine.

If you have ANY of these conditions, or if you are not sure, then DO NOT TAKE the medicine. DO talk to your healthcare provider as soon as possible.

If you are pregnant, take the medicine, but get a full check-up afterward.

How to Take Zithromax®

Usually, azithromycin comes in pills, but sometimes it comes as a liquid or as a powder to be mixed with water. If you need help taking the medicine, contact the pharmacy or clinic where the medicine was given to you.

Most people will get four pills. If this is what you have, you should take all four pills at the same time, with water. You need to take all four of the pills to cure the infection.

Often, Zithromax® pills contain 250 mg of the medicine (4 pills = 1000 mg total). Do NOT take antacids for one hour before or two hours after taking the Zithromax® pills.

Private STD consultations

Side Effects

Some people get a mild upset stomach, diarrhea, or vaginal yeast infection after taking this medicine. These usually are mild and don’t last long. If they become more severe, then contact your healthcare provider to get treatment.

Some people vomit up the medicine shortly after taking it. If you vomit up the medicine after you take it, contact your healthcare provider to get more, or different, medicine.

IF YOU HAVE SIGNS OF AN ALLERGIC REACTION, such as trouble breathing, dizziness, throat tightness, swelling of lips or tongue, or hives (very itchy skin bumps or welts), call 911 or go to the Emergency Room immediately.

Next Steps After You Take The Medicine

Do not have sex for the next seven days. If you do have sex less than seven days after taking medicine, be sure to use a condom. It takes seven days for the medicine to cure chlamydia.

During that time, you could still pass this infection on to a sex partner. Condoms may help prevent spread, but the safest way to make sure you don’t pass the infection on to anyone is to not have sex for seven days.

If you have other sex partners, tell them you are getting treated for chlamydia so they can get tested and treated if necessary. Contact your county health department to talk to someone who can help you choose the best way to tell your partners.[1]

Special Note: Azithromycin Or Doxycycline For Asymptomatic Rectal Chlamydia

Regular screening for rectal chlamydia is recommended for men who have sex with men. The estimated prevalence of rectal chlamydia among men attending STD clinics is approximately 9%. There is also increasing concern about rectal chlamydia in women and its possible role in urogenital infection through autoinoculation, which increases the risk of reproductive complications associated with infection.

Until recently, most guidelines have recommended treatment for rectal chlamydia consisting of either doxycycline (at a dose of 100 mg twice a day for seven days) or azithromycin (in a single 1 g dose) on the assumption that both regimens were efficacious. However, a number of observations have led practitioners in several countries to change their guidelines to recommend doxycycline as a first-line treatment. These observations include a systematic review of observational data indicating that doxycycline may be approximately 20% more efficacious than azithromycin for the treatment of rectal chlamydia, along with increasing concern about resistance to azithromycin in other STIs.

The attraction of azithromycin for the treatment of chlamydia has been its efficacy as a single-dose therapy. In the absence of a randomized, controlled trial that directly compares azithromycin with doxycycline for rectal chlamydia, any decision about changing the current guidelines could be considered premature. Therefore, researchers performed the double-blind, randomized, controlled Rectal Treatment Study to compare single-dose azithromycin with a seven-day course of doxycycline in a population of men who have sex with men.

Results from this trial have shown that a seven-day course of doxycycline was superior to single-dose azithromycin in the treatment of rectal chlamydia infection among men who have sex with men.[2]

Everlywell Offers STD Consults And Chlamydia Screening Tests

Everlywell offers online STD consults in two hours or less. Fast and discreet STD care is just a click away. Create your health profile and complete an insurance coverage check (if paying with insurance). Book an on-demand video call and speak to a clinician within 2 hours. Get treatment and have a prescription sent directly to your pharmacy (if applicable).

At-home diagnostic kits for several STDs are also available, such as for chlamydia.

Understanding Oral Gonorrhea Treatment

How Long Does It Take For Antibiotics To Work?

Can Penicillin Treat STDs?


  1. You just found out that you may have been exposed to chlamydia, a sexually transmitted disease (STD)… Now what? Oregon Health Authority: Public Health Division. Accessed on 9/8/2023.
  2. Lau A, Kong FYS, Fairley, CK, et al. N Engl J Med 2021; 384:2418-2427 DOI: 10.1056/NEJMoa2031631
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