A Double-Blind Randomized Placebo-Controlled Pilot Study of Azithromycin in Youth with Acute-Onset Obsessive-Compulsive Disorder.
Level 2 - randomized trial
Individual double-blind randomized placebo-controlled pilot trial
PubMed 28358599 · doi:10.1089/cap.2016.0190
What was done
Thirty-one youth aged 4–14 years with pediatric acute-onset neuropsychiatric syndrome (PANS) and acute-onset obsessive-compulsive disorder (OCD) were randomized in a double-blind design to receive either azithromycin (10 mg/kg up to 500 mg/day; n = 17) or placebo (n = 14) for 4 weeks. Both groups received twice-daily probiotics. Primary outcomes were OCD severity measured by the Clinical Global Impressions Severity scale (CGI-S OCD) and the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS). Responder rates (CGI-I OCD), tolerability, and ECG QTc intervals were also evaluated.
What was found
Azithromycin showed significantly greater reductions on the CGI-S OCD compared with placebo at week 4 (p = 0.003), but no statistically significant difference was detected on the CY-BOCS. A higher proportion of participants met CGI-I responder criteria with azithromycin than with placebo (41.2% [n = 7] vs. 7.1% [n = 1]; p = 0.045). Greater baseline tic severity was associated with enhanced response on the CGI-S OCD. Adverse events included significantly more loose or abnormal stools in the azithromycin group (p = 0.009) and a trend toward increased ECG QTc duration (p = 0.060); there were no dropouts due to side effects.
Why it matters
This pilot trial provides initial randomized evidence suggesting azithromycin may benefit children with acute-onset PANS-related OCD, particularly those with comorbid tics, though mixed outcome findings and potential QTc prolongation warrant caution.
Limits
The study was a small pilot trial (n = 31), limiting statistical power. Results were mixed across primary endpoints, showing efficacy on clinician global severity but not on the CY-BOCS. The 4-week follow-up was too brief to assess long-term efficacy, relapse, or safety risks.
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