Azithromycin no longer first line for chlamydia: new guidance
Editor’s note: This story has been updated with the correct special management regimens for complicated Mycoplasma genitalium infection. For the two combination treatment scenarios involving doxycycline, the article previously stated a dose of ‘100mg daily’, but this should have read ‘100mg twice daily’. This was based on an error in the original article published by Sexual Health.
GPs are now advised to prescribe doxycycline instead of azithromycin as first-line therapy for chlamydia infections in all anatomical sites.
In a major update to STI management guidelines, a one-week course of doxycycline (100mg oral, twice daily) is the preferred treatment for uncomplicated genital or pharyngeal chlamydia and asymptomatic anorectal infection.
For symptomatic anorectal chlamydia, a three-week course of the antibiotic is advised.
In both instances, the broad-spectrum antibiotic also acts as a “pre-treatment” for concurrent Mycoplasma genitalium.
A 1g oral dose of azithromycin — the former standard treatment of choice — is now listed as an alternative treatment for isolated genital chlamydia and can be used “if there are concerns about poor adherence”.
“If using azithromycin for anorectal infections, we recommend azithromycin 1g oral stat and repeat in 12–24 hours based on pharmacodynamics,” the authors wrote in the latest issue of Sexual Health.
Sydney sexual health physician Professor Basil Donovan said the switch reflected doxycycline’s superiority over azithromycin for treating chlamydia.
“Even though [doxycycline] seems to be old-fashioned, it is a much better antibiotic than we realised,” Professor Donovan, who is head of the sexual health program at UNSW Sydney’s Kirby Institute, told Australian Doctor.
“It has a role in treating antibiotic-resistant M. genitalium, it is actually quite an effective treatment for syphilis and it is the best treatment for chlamydia.”
Recommendations for contact tracing have also been rewritten to advise doctors against immediately treating all sexual contacts for chlamydia and to instead test exposed sites and await results.
The guidelines also state that HIV and syphilis tests should be a routine part of STI screening in a bid to increase opportunistic testing, reflect HIV elimination goals and curb the rise in syphilis notifications.
Professor Donovan said Indigenous women were of most concern for these two infections but often went untested even when diagnosed with another STI.
“Indigenous communities have a syphilis outbreak at the moment, and HIV keeps threatening to go up in that population,” he said.
Other guideline changes include the addition of sex-associated diarrhoea in response to reports of increasing drug-resistant shigellosis among men who have sex with men.
Expert local advice and stool culture when treating diarrhoea in this population are now recommended.
And in response to rising antimicrobial resistance, the M. genitalium treatment recommendations for when first-line therapy fails or is contraindicated have also been updated.
The guideline author now suggest consideration of either of the following:
- pristinamycin 1g three times daily combined with doxycycline 100mg twice daily for 10 days
- minocycline 100mg twice daily for 14 days
- doxycycline 100mg twice daily combined with sitafloxacin 100mg daily twice daily for seven days
These treatment options cure an estimated 70-90% of macrolide-resistant M. genitalium infections, the authors say.
More information: Sex Health 2022; 11 Nov.
