Fluoroquinolones associated with retinal detachment

Current users of oral fluoroquinolones are nearly five times more likely to have a retinal detachment than nonusers, although the absolute risk was small, a study found.

To examine the association between use of oral fluoroquinolones and the risk of developing a retinal detachment, researchers conducted a nested case-control study of patients in British Columbia, Canada, who had visited an ophthalmologist between January 2000 and December 2007.

Current users were those with a prescription that overlapped the index date. A recent user was defined as having a prescription 1 to 7 days prior to the index date, and a past user was defined as having a prescription 8 to 365 days before the index date.

As an additional control, researchers also examined the risk of retinal detachment against two drug classes not associated with retinal detachment: oral β-lactam antibiotics (all oral penicillins and cephalosporins) and short-acting β-agonists.

Results appeared in the April 4 Journal of the American Medical Association.

Among the cohort of 989,591 patients, 4,384 cases of retinal detachment and 43,840 corresponding controls were identified. Current use of fluoroquinolones was associated with a higher risk of developing a retinal detachment (3.3% of cases vs. 0.6% of controls; adjusted rate ratio [ARR], 4.50; 95% CI, 3.56 to 5.70). Neither recent use (0.3% of cases vs. 0.2% of controls; ARR, 0.92; 95% CI, 0.45 to 1.87) nor past use (6.6% of cases vs. 6.1% of controls; ARR, 1.03; 95% CI, 0.89 to 1.19) was associated with a retinal detachment.

There was no evidence of an association between retinal detachments and β-lactam antibiotics (ARR, 0.74; 95% CI, 0.35 to 1.57) or short-acting β-agonists (ARR, 0.95; 95% CI, 0.68 to 1.33).

The absolute increase in the risk of a retinal detachment associated with fluoroquinolones was 4 per 10,000 person-years. The number needed to harm was 2,500 for any use of fluoroquinolones.

The retina is attached to the cortical vitreous by collagen fibers, and fluoroquinolones have been shown to interfere with collagen synthesis. Just two doses of oral ciprofloxacin can reach antibacterial concentration in the vitreous, the authors noted. Although the absolute risk is small, fluoroquinolones are a commonly prescribed drug and 40% of people who experience a detachment could permanently lose at least some visual acuity, they noted.