[Question #4526] Chlamydia and Zithromax

27 months ago
My girlfriend was diagnosed with Chlamydia.  I don't have symptoms.  She had vaginal discomfort.  Our doctors both gave us Zithromax.  I was given 1 gram to take at the same time and she was given a Z-Pak (500mg day one then 250 mg for the next several days). 

Everything I see online states my dose is the correct treatment if not using Doxycycline.  I cant find anything stating her treatment is recommended.  I'm wondering if she is sufficiently treated with that dosing?  We have had anal sex too and she didnt tell her doctor. Will her treatment cure her if she has the infection in her rectum too?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
27 months ago
Welcome to the forum. Thanks for your question.

I'm glad to hear you were both treated. Were you also tested for it? Doesn't matter too much -- generally best to confirm the diagnosis, but the most important thing is to treat without waiting for test results.

Correct that a single 1 gram dose of azithromycin is one of the two main recommended treatments. The more prolonged azithromycin course given to your partner has never been studied for its effectiveness against chlamydia, but it is very likely to be effective and I would not recommend changing treatment on that account. (However, if she has only just starrted treatment, she could take 4 pills at once (250 mg x 4 = 1 gram) instead of spreading it out over the next few days. But she really should discuss it with her doctor and make sure s/he approves. Maybe this will be an opportunity to educate her doctor about the proper dose!)

Your partner's rectal exposure and a good chance of rectal infection may be important. Recent research shows azithromycin works against chlamydia a little less reliably than doxycycline:  for genital infection, probably around 2-5% treatment failure rate; and for rectal infection, azithromycin fails 10-15% of the time. In contrast, doxycycline for 7 days almost never fails to cure chlamydia in both the genital tract and rectum. Knowing rectal infection was possible in your partner, most experts would have a) tested her for rectal infection and b) used doxycycline instead of azithromycin, assuming the doctor believed your partner would reliably complete all 7 days treatment.

What to do now? Because of the slightly higher chance of treatment failure with azithromycin -- especially in your partner's rectum, but possibly for genital infection in both of you -- it would be reasonable for both of you to be retested in 3-4 weeks to be sure you were cured. In your partner, that should include both vaginal and rectal swabs. Don't do it before 3 weeks. Up til then, chlamydia DNA may persist even though the organism was killed, giving a false positive test result. In the meantime, aftrer a few dqys it is safe for the two of you to resume sex together. Most likely the azithromycin will work, and if not, no harm is likely in the meantime until you both are retested.

Finally, you both should have been tested for gonorrhea, syphilis, and HIV -- routine tests for anyone with any new STD. Gonorrhea testing probably was done, at least in your partner:  in most labs, routine gonorrhea or chlamydia testing automatically checks for the other.

I hope this information is helpful. Let me know if anything isn't clear.

HHH, MD
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