Azithromycin shows equal efficacy to doxycycline in meibomian gland dysfunction treatment
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Key takeaways:
- Azithromycin had fewer gastrointestinal adverse events compared with doxycycline.
- Less frequent dosing with azithromycin may lead to better treatment compliance.
Azithromycin showed equivalent efficacy to doxycycline in treating moderate to severe meibomian gland dysfunction, with reduced dosing and potentially fewer gastrointestinal adverse events, a study found.
As reported by the authors, meibomian gland dysfunction (MGD) has a global prevalence of 35.8% and is more common among East Asian people (51.2%), including Thai people (46.2%). The study was carried out at a tertiary referral center in Thailand between September 2018 and May 2022.
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The study included 137 eyes of 137 patients. Patients were randomly assigned to receive oral doxycycline 100 mg twice a day for 6 weeks or oral azithromycin 1 g once a week for 3 weeks. To achieve full masking, the azithromycin group received placebo pills to equal the number of pills taken daily by the other group. Objective and subjective MGD scores were evaluated at 6 weeks and 8 weeks.
Both antibiotics were effective in reducing the signs and symptoms of MGD. A 3-week course of weekly oral azithromycin was equivalent to a 6-week course of oral doxycycline. Gastrointestinal adverse events, including nausea, vomiting, dyspepsia, abdominal cramping and decreased appetite, were fewer in the azithromycin group (three cases) than in the doxycycline group (11 cases). Two patients in the doxycycline group had “unbearable” gastrointestinal symptoms, leading to discontinuation of the therapy.
In moderate to severe MGD, doxycycline is commonly recommended. “However, compliance can be a problem, as a consequence of the long course of therapy and frequent gastrointestinal adverse events,” the authors wrote.
With equivalent efficacy, fewer frequent side effects and a less frequent dosing regimen, azithromycin could be an attractive alternative to doxycycline in patients with MGD. “However, longer-term follow-up in each group would be needed to determine if these outcomes persist for this chronic condition,” they wrote.
References:
- FDA drug safety communication: Azithromycin (Zithromax or Zmax) and the risk of potentially fatal heart rhythms. https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-azithromycin-zithromax-or-zmax-and-risk-potentially-fatal-heart. Updated Feb. 14, 2018.
- Giudicessi JR, et al. Cleve Clin J Med. 2013;doi:10.3949/ccjm.80a.13077.
- Greene JB, et al. JAMA Ophthalmol. 2014;doi:10.1001/jamaophthalmol.2013.5295.
- Mercuro NJ, et al. JAMA Cardiol. 2020;doi:10.1001/jamacardio.2020.1834.
Perspective
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This study supports the equivalency at 8 weeks of pulse-dosed oral azithromycin at 1 g oral weekly for 3 weeks, as first reported by Greene and colleagues, with oral doxycycline 100 mg twice daily. Both medications performed equally as well at improving meibomian gland function and dry eye symptoms. There were more gastrointestinal side effects in this study with oral doxycycline.
The take-home message is that in patients with moderate to severe meibomian gland dysfunction that is not responding to conventional measures, either pulse-dosed oral azithromycin or oral doxycycline can be used to good effect. The relative ease of pulse-dosed oral azithromycin and the reduced gastrointestinal side effects may support azithromycin over doxycycline as a preferred treatment.
One factor that clinicians need to be aware of that is not mentioned in this study is the potential of azithromycin to cause QT interval prolongation and precipitate a fatal torsades des pointes cardiac arrhythmia, for which it carries an FDA black box warning. This appears to be a greater risk when patients are taking oral hydroxychloroquine but can also occur with patients who are at risk of QT prolongation due to other conditions. Thus, appropriate caution should be taken when considering the use of oral azithromycin.
There are two very different treatment regimens in this study — one is chronic administration of doxycycline vs. pulse dosing of oral azithromycin. Understanding how long the treatment effect works and what happens after stopping either medication will be helpful in counseling patients with regards to the time course and expectations of need for re-treatment.
In general, there is still so much we do not understand about meibomian gland dysfunction, starting with why oral antibiotics work in the first place. We are in the infancy of understanding the complexities of the tear film, and studies such as this are helpful in improving our treatment options for these patients.
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