[Question #2237] Azithromycin Ineffective?

44 months ago

Hi there, I posted previously and received great help from Dr Handsfield. 

To cut a long story short, my partner was diagnosed with Chlamydia on the 2nd of May, negative for all other STD'S including HIV. I was tested the 3rd of May and had to wait approximately a week for results (Came back negative for HIV but positive for Chlamydia, negative for all other STD’s).

Despite waiting for results, I was diagnosed 1g of Azithromycin by the NHS Gum Clinic here within the UK, as they knew of my partner’s recent positive test for Chlamydia. My partner was also given the same. Approximately 48 hours after treatment, I and my partner foolishly engaged in unprotected vaginal sex and oral sex multiple times over a period of 3 to 4 days.

We were on holiday abroad. We came quickly came to our senses when back in the UK and went back to the clinic and received a further 1g each of Azithromycin. After taking Azithromycin for the second time, my girlfriend developed small hive like rash from Azithromycin on her shoulders, lower back and legs. They was not severe.  I took her to an emergency walk in clinic to be safe. The Nurse informed my partner she had a reaction to the medication. She was given lotion and no other alternative antibiotics for the Chlamydia. We waited approximately 18 days (Sunday the 28th of May) before engaging in unprotected sex.

After sex, today I have noticed a burning sensation just as my urine comes out, eventually it passes. It felt like I had discharge also, after I urinated I did squeeze the tip of penis to find discharge but I wasn't sure if this was urine rather than discharge. My girlfriend has also stated she felt burning after the sex we had.

My questions are

1) as I am 100% certain I and my partner have no other sexual partners and we haven't engaged in any sexual contact for 18 days, has the Azithromycin failed?

2) Did my girlfriends 'reaction' to this drug also make the antibiotic ineffective?

3) I've taken Anti Biotics years ago for acne and I remember then I built up a resistance. Could I be resistant to Azithromycin?

4) Do you see Azithromycin fail often in your history within this field?

5) Does it sound like or possible we STILL have Chlamydia?

5) What should I do now?

Kind regards,


H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
44 months ago
Welcome back to the forum. Interesting to learn that you also tested positive for chlamydia. That information wasn't available at the time of your previous thread. It shows your wife's positive test was not a false positive; clearly you both were infected. The most likely scenario is that she had a persistent infection, going back to some distant past sexual exposure. But as we discussed last time, you'll probably never know for sure.

As for the current situation, it is unlikely you or your partner still has chlamydia at this time. It wasn't as unsafe to begin having sex toether on your holiday as you thought. You had both been treated, so the chance either of you still had a transmissible infection during the holiday was very low. In any case, as a precaution you were then both re-treated on retrun. The rather mild (or even vague) symptoms you report now are not typical for chlamydia. In any case, symptoms are not reliable in judging judge whether a chlamydial infections is persisting. To your specific questions:

1,5) There is no reason to ssupect azithromycin has failed. You can safely continue sex with your partner, without awaiting further test resuts.

2) Having side effects does not alter the effectiveness of any antibiotic against infection.

3) This reflects a popular misconception. People do not develop resistance to antiibioitcs. Some bacteria become resistant to antibiotics to which they are exposed, but if the bacteria causing an infection is susceptible, the antibiotic will work, regardless of how often or in what doses that person has previously used that antibiotic. And it so happens that chlamydia is one of the minority of bacteria that never develops antibiotic resistance. Every chlamydia strain is invariably and uniformly susceptible to azithromycin and the tetracyclines (e.g. doxycycline) and a few others. 

4) We discussed the data on azithromycin failure in your other thread. The standard single dose treatment with 1 gram fails to cure around 2-5% of infections, somewhat more (10-15%) if rectal infection is present. FYI, this does not conflict with answer (3). Such failures are not fully understood, but they are not because of antibiotic resistance. Whether or not I have seen azithromycin treatment failures is irrelevant. Rare things happen. Similarly, whether or not I have ever cared for a patient struck by lightning has no bearing on your odds of being struck.

6) What to do now? Nothing. Of course if your symptoms worsen, especially if you develop an obvious urethral discharge, return to the GUM clinic for further evaluation. Otherwise, I would recommend that both you and your partner be retested in 2-3 months (urine for you, vaginal swab for her). I imagine the GUM clinic might already have given you this advice.

If and when you return to the clinic, or if you would like to review this with them, consider printing out this thread as a framework for discussion. Their doctors know as much about all this as I do, and I'm pretty confident they will endorse all I have said.

I hope that helps. Best wishes to you and your partner.

44 months ago
Thanks for your knowledge and response into the matter, which I must admit does make me feel slightly better and reassured. 

I will test again in approximately 2 to 3 months to be sure.

I only have a few outstanding questions to try and put my anxiety to rest and offer further clarification. 

1) You state I can continue to have sex with my partner. Should this be protected to be 100% sure we are not passing the infection back and forth? 

2) Say if me and my partner do still have Chlamydia and the treatment failed. Would our bodies eventually clear the infection on itself? Even if we continue with protected sex?

3)  How long does it normally take for both female and male to clear the infection on itself?

In closing, I thank for you assistance and the service you have provided in your long career.

Kind regards,


H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
44 months ago
1) Since single dose azithromycin fails to cure chlamydia 2-5% of the time, there is a slight chance either of you could still be infected and transmit it back and forth. But the chance is sufficiently low that our routine advice in expert STD/GUM clinics is that couples in your situation can and should continue unprotected sex together.

2,3) Yes. The immune system typically clears chlamydia, probably an average of 2-3 months in men and up to a year in women. (These are very rough estimates, without good data.) OTOH, this whole situation apparently may have arisen because your partner had a longstanding infection (years?) that had not cleared, so it seems possible that clearance may be harder to predict in her.

Another option is to ask the GUM clinic about prescribing doxycycline for both of you. The standard 1 week course of doxycycline is virtually 100% effective, without the occasional treatment failures seen with azithromycin; and in chlamdia in animals, doxy appears to be more effective than azithro in eradicating the organism from the GI tract. In my STD clinic, we now uniformly prescribe doxy rather than azithro whenever there is a higher risk of rectal/GI infection (e.g., gay men, women with positive rectal tests). OTOH, I believe it would be entirely safe to not be re-treated now, but wait for final tests you and your partner in 3 months. If either of you remains positive, doxycycline definitely would be the way to go. But that's not likely to happen. Anyway, as I said above, it can't hurt to have a discussion with the GUM clinic (especially a GUM specialty physician rather than nurse clinician), perhaps printing and using this thread as a framework for discussion.

That completes the two follow-ups and replies included with each question and so ends this thread. There should be no need for further discussion, especially if any further chlamydia testing shows negative results. But feel free to post a new question in the unlikely event either of you again tests positive.

Good luck--  HHH, MD