Methods:

This is an observational study using a large French insurance database with >66 million enrollees. Fluoroquinolone cases were enrollees ≥18 years who had a symptomatic intracranial dissection between 2010 and 2015, and who had been prescribed a fluoroquinolone (and not amoxicillin) in the 180 days before their index event. Amoxicillin cases were enrollees ≥18 years who had a symptomatic intracranial dissection between 2010 and 2015 and who had been prescribed amoxicillin (and not a fluoroquinolone) in the 180 days before the index event. Drug exposures were measured using out-of-hospital prescription reimbursements. The time period of interest was 30 days prior to the index event and was compared to three different control time periods: 180-151 days, 150-121 days, and 120-91 days prior to the index event. The outcome of interest was the ratio of the estimated odds ratio (OR) for fluoroquinolone over the estimated OR for amoxicillin.