Study supports link between fluoroquinolones and aortic aneurysm

Fluoroquinolone antibiotics are associated with an increased risk of aortic aneurysm or dissection, a study shows.

The findings, published in the BMJ, found a 66% increased risk of aortic aneurysm or dissection in people who received the class of antibiotics during the 60-day period after treatment initiation, compared with those who received amoxicillin.

The study used nationwide registry data from Sweden to compare 360,088 episodes of fluoroquinolone use (78% ciprofloxacin) matched to an equal number of amoxicillin use episodes.

Within 60 days of the first prescription being filled, the rate of aortic aneurysm or dissection was 1.2 vs 0.7 cases per 1000 person-years, respectively.

In secondary analyses, the researchers found no significant relationship between fluoroquinolone use and aortic aneurysm or dissection 61–120 days of initiation. And 41% of events in fluoroquinolone-treated patients occurred in the first 10 days.

They also found that most of the association was driven by the risk of aneurysm, which was raised by 90% in the initial 60-day period.

The results add to a growing body of evidence linking fluoroquinolones to aortic aneurysms. However, the authors note that the absolute risk still remained small, equating to an addition 82 incidents per million treatment episodes.

It is thought that fluoroquinolones have a damaging effects on the extracellular matrix in the vascular wall. They carry a boxed warning regarding these mechanisms and, in 2016, the European Medicines Agency launched a safety assessment of the drug class following two reports from the UK linking them to aortic aneurysm.

The research team, led by Björn Pasternak from the Karolinska Institutet in Stockholm, concluded that their findings lend support to this purported association.

However, they added: “Before these results are used to guide clinical decision making, the collective body of data on this safety issue should be scrutinised by drug regulatory authorities and weighed, together with other safety issues with this drug class.”