Chlamydia is treated with antibiotics, and the standard first-line treatment is doxycycline taken twice daily for seven days. This cures the infection in the vast majority of cases. Azithromycin, once the go-to option as a single-dose treatment, is now considered an alternative rather than the top choice.
Doxycycline: The Preferred Treatment
Doxycycline is the most commonly prescribed antibiotic for chlamydia in men and non-pregnant women. The typical course is 100 mg taken by mouth twice a day for seven days. It works by shutting down the bacteria’s ability to build proteins it needs to survive, effectively starving the infection at a cellular level.
Recent clinical evidence has shown doxycycline outperforms azithromycin, particularly for rectal chlamydia infections, which is why guidelines have shifted to favor it. The seven-day course requires more commitment than a single pill, but the higher cure rate makes it the better option for most people.
Tips for Taking Doxycycline
A few practical things matter during your week of treatment. Take each dose with food and a full glass of water, and stay upright for at least an hour afterward to avoid irritation in your esophagus. Avoid dairy products, antacids, and supplements containing iron, calcium, or magnesium within two hours of your dose, since these can block absorption. Doxycycline also makes your skin more sensitive to sunlight, so wear sunscreen or cover up if you’ll be outside.
Azithromycin and Other Alternatives
Azithromycin is still used when doxycycline isn’t an option. Its main advantage is convenience: it’s a single 1-gram dose taken all at once. For people who are unlikely to complete a full seven-day course, that simplicity can be a real benefit. However, its cure rates for certain types of chlamydia infection, especially rectal, are lower than doxycycline’s.
Levofloxacin, a fluoroquinolone antibiotic, is another backup option at 500 mg once daily for seven days. Ofloxacin, a related drug, is also sometimes used at 300 to 400 mg twice daily for seven days. These are typically reserved for people who can’t tolerate either doxycycline or azithromycin. Erythromycin, an older antibiotic once commonly used, is no longer recommended because its frequent gastrointestinal side effects (nausea, cramping, diarrhea) make it hard for people to finish the full course.
Treatment During Pregnancy
Pregnancy changes the equation significantly. Doxycycline is off the table during the second and third trimesters because it can affect fetal tooth development. Instead, azithromycin as a single 1-gram dose is the recommended treatment for pregnant women. Clinical experience and published studies support its safety and effectiveness during pregnancy.
Amoxicillin (500 mg three times daily for seven days) is listed as an alternative, though there are some concerns from animal and lab studies about whether chlamydia can persist after exposure to penicillin-type antibiotics. Levofloxacin poses potential risks to developing cartilage in the fetus and complications during breastfeeding, so it’s generally avoided.
Follow-up testing is especially important during pregnancy. A repeat test about four weeks after finishing treatment confirms the infection is gone, and another retest is recommended three months later. Untreated or persistent chlamydia during pregnancy can cause serious complications for both the mother and baby.
What Happens After Treatment
You should avoid sex for seven days after starting treatment (or seven days after a single-dose azithromycin) to prevent passing the infection to a partner or getting reinfected. If symptoms persist after completing your course, a follow-up test can check whether the bacteria have been fully cleared. Testing too soon, within the first few weeks, can sometimes pick up leftover DNA from dead bacteria and produce a misleading positive result, so the four-week mark is the earliest reliable window for retesting.
Reinfection is common, not because the antibiotics failed but because people are re-exposed by an untreated partner. Getting retested about three months after treatment is recommended for this reason.
Making Sure Your Partner Gets Treated
Treating chlamydia in just one person doesn’t solve the problem if a sexual partner still carries the bacteria. Reinfection from an untreated partner is one of the most common reasons people test positive again shortly after treatment. Ideally, your current sexual partners should be evaluated and treated at the same time you are.
When a partner can’t or won’t visit a provider, many states allow something called expedited partner therapy. This means your healthcare provider can give you a prescription or medication to pass along to your partner directly, without requiring that partner to come in for a separate exam. The CDC considers this a useful option, particularly for male partners of women diagnosed with chlamydia.
Antibiotic Resistance Is Not Yet a Concern
Unlike gonorrhea, which has developed alarming resistance to multiple antibiotics, chlamydia remains highly susceptible to current first-line treatments. National surveillance studies consistently show low resistance rates. Extremely rare cases of reduced susceptibility to tetracyclines, macrolides, and fluoroquinolones have been observed in lab settings, but these haven’t translated into widespread treatment failures in real-world clinical use. For now, standard antibiotic regimens remain effective for the overwhelming majority of infections.