Azithromycin Gel for Lyme Prevention: What the Trial Found
Preventing Lyme disease after a tick bite remains a clinical challenge. A topical azithromycin gel was studied as a possible early intervention, but results did not support its effectiveness.
This raises an important question: can a topical antibiotic prevent Lyme disease after a tick bite? Findings from a clinical trial suggest that this approach may have limited benefit.
In a randomized, double-blind, placebo-controlled trial published in The Lancet Infectious Diseases, investigators evaluated a 10% azithromycin gel applied after tick bites.
Study Findings
In a post hoc analysis of 134 subjects, the gel prevented erythema migrans rashes in 6 individuals.
In 2 additional cases, the gel delayed the onset of erythema migrans by 33 and 51 days.
However, the trial did not demonstrate that azithromycin gel prevented Lyme disease.
Limitations of Topical Prevention
While the gel appeared to affect the timing or appearance of rashes in a small number of cases, this did not translate into meaningful prevention of infection.
The findings highlight the difficulty of preventing Lyme disease after a tick bite with topical therapies alone.
Clinical Perspective
Although the idea of a simple topical treatment is appealing, this study suggests that azithromycin gel should not be relied upon for Lyme disease prevention.
Patients may benefit from proven strategies such as tick bite prevention, early recognition of Lyme disease symptoms, and timely medical evaluation following a tick bite.
Learn more about prevention strategies in the Lyme disease prevention hub.
References
- Schwameis M et al. Topical azithromycin for Lyme prevention. Lancet Infect Dis. 2016.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
Thank you for this post, Dr Cameron. This was widely reported in the press as being a trial which showed that the gel had “promise” as a treatment for infected bites. As here: https://www.news-medical.net/news/20161220/Antibiotic-gel-shows-promise-in-preventing-onset-of-Lyme-borreliosis-following-tick-bite.aspx
It is a shame the gel failed to work
Is Azithromycin in tablet form affective to treat Lyme?
Oral Zithromax has been effective in most studies. Doxycycline beat Zithromax in on study my Massaroti in 1992.
Because the company making the gel was able to get special status from CDC, called QIDPb status, they get two tries at doing a stage III clinical trial such as this. So long as they have the money, they a redo to look only at the subgroup that showed some benefit. This worries me, because doing a placebo controlled study of high risk tick bites resembles Tuskegee to me: they are knowingly allowing the placebo group to get sick, in order to get a statistically more favorable outcome. Even if the gel helps a segment of people, there is no way for them to identify themselves in advance, so if it’s approved, everybody, not just the subgroup, will potentially use this, and forgo oral antibiotics. One of their medical advisors is Dr. Wormser. I think they might potentially raise the money because the product would be over the counter, this saving instance companies money they would have spent on doxycycline or Amoxicillin.
I also have concerns with trying to sell a cream based on subgroup analysis.