Azithromycin is an antibiotic still used for a handful of bacterial STIs, but it is no longer the go-to drug it once was. Current CDC guidance now favors doxycycline for chlamydia and reserves the single ceftriaxone injection for gonorrhea. Azithromycin keeps a role in specific situations, but where you'd reach for it has narrowed sharply.
antibiotics clear them
medicine controls, doesn't cure
| Item | Value |
|---|---|
| Bacterial & parasitic (chlamydia, gonorrhea, syphilis, trich) | curable — antibiotics clear them |
| Viral (herpes, HIV, hepatitis B, HPV) | managed — medicine controls, doesn't cure |
The essentials: where azithromycin stands now
For years a single oral dose of azithromycin was the standard treatment for chlamydia, prized because it's one dose and easy to take. That has shifted. The CDC's 2021 STI Treatment Guidelines moved doxycycline ahead of azithromycin as the preferred chlamydia treatment, with azithromycin kept as an alternative for people who can't reliably take a multi-day course or who are pregnant CDC, 2021.
Its bigger change is what azithromycin no longer does. It used to be paired with ceftriaxone to treat gonorrhea, but gonorrhea has grown resistant to nearly every antibiotic once used against it. The recommended treatment now is a single ceftriaxone injection on its own, and azithromycin was dropped from that combination CDC, drug-resistant gonorrhea.
Whether an STI can be cured at all depends on its cause. Bacterial and parasitic infections — chlamydia, gonorrhea, syphilis, trichomoniasis — are curable with the right antibiotic. Viral infections like herpes, HIV, hepatitis B, and HPV are controlled with medicine but not cured. Azithromycin treats certain bacteria and does nothing for a virus.
How azithromycin works against bacterial STIs
Azithromycin is a macrolide antibiotic. It blocks bacteria from making the proteins they need to grow and multiply, which lets your immune system clear the infection. Because the drug lingers in tissue for days after a single dose, one course can keep working long after you swallow the pills, so it could be given as a one-time treatment for chlamydia.
That same long half-life can backfire. If a bacterium isn't fully susceptible, lingering low levels of the drug can encourage resistance. That's part of the reasoning behind moving chlamydia to doxycycline, which has held up better in studies of certain infections, and behind reserving the right drug at the right dose for gonorrhea, where keeping the disease treatable depends on not under-dosing.
Practical details: what taking it is actually like
Treatment for a bacterial STI is usually a short course of pills or a single shot. It's often free or low-cost at a health department or Planned Parenthood clinic, and in many states your partners can be treated without their own appointment through expedited partner therapy — your clinician sends a prescription or medication home for them.
Most people start feeling better within a few days of starting treatment, but that's not proof of cure. Some infections call for a follow-up test-of-cure or a retest weeks to months later, because symptoms can fade before the bacteria are fully gone. Take the full course exactly as prescribed even if you feel fine, and make sure partners are treated too. Stopping early or skipping partner treatment lets an infection quietly persist or bounce straight back.
Hold off on sex until you and your partners have finished treatment and any wait period your clinician gives — often about a week after a single-dose treatment — so you don't pass the infection back and forth. The two most common mistakes are stopping pills the moment symptoms ease and assuming a partner is fine because they have no symptoms; many STIs are silent.
How azithromycin compares to the other STI drugs
| Drug | Typically used for | What to know |
|---|---|---|
| Azithromycin (pills) | Chlamydia (alternative), select other bacterial STIs | Often a single dose; now second-line for chlamydia behind doxycycline |
| Doxycycline (pills) | Chlamydia (preferred) and others | Can cause stomach upset and sun sensitivity — take with food and avoid strong sun |
| Ceftriaxone (injection) | Gonorrhea | A single shot; soreness at the injection site is the main side effect |
| Metronidazole / tinidazole (pills) | Trichomoniasis, bacterial vaginosis | Can react badly with alcohol — avoid alcohol during and shortly after treatment CDC, trichomoniasis |
What azithromycin does not cover
Antibiotics treat bacterial STIs, not viral ones. Taking azithromycin for herpes, HIV, hepatitis B, or HPV does nothing for the infection and contributes to antibiotic resistance. It also isn't the right drug for trichomoniasis, a parasite treated with metronidazole or tinidazole, and it's no longer used to treat gonorrhea on its own.
For skin-based conditions like molluscum, oral antibiotics aren't the answer either — if that's what brought you here, see the dedicated guide on molluscum contagiosum treatment & removal options. And there's no over-the-counter product or home remedy that cures any bacterial or viral STI. Yogurt, garlic, douching, and detoxes do not work. You need the specific prescription medicine and a real diagnosis, which starts with the right test.
When to see a clinician
See a clinician if you have symptoms like unusual discharge, burning with urination, sores, or pelvic pain, or if a partner tells you they tested positive. Don't self-prescribe leftover or borrowed azithromycin. The wrong drug or dose can mask an infection without curing it and can drive resistance. A clinician confirms what you actually have and matches it to current guidance.
The first step is almost always a test rather than a pill. If you're unsure whether you're due, learn when to test after exposure so you don't test too early and miss an infection, then get tested before starting any treatment. Treatment without a diagnosis is a guess.