Evaluation of adverse events in self-reported sulfa-allergic patients using topical carbonic anhydrase inhibitors

To investigate whether a self-reported history of allergy to sulfa-based drugs is a predictor for subsequent adverse reactions to topical carbonic anhydrase inhibitors (CAIs).

A retrospective case-controlled cohort study via chart review was performed on 1,287 patients with a diagnosis of glaucoma. The outcome measure was the development of an adverse reaction (either ocular, systemic, or both) within at least 30 days after receipt of 1 of 4 classes of topical glaucoma medications: CAIs (dorzolamide and brinzolamide), prostaglandin analogues, beta-adrenergic blockers, and alpha2-adrenergic agonists.

Patients with a self-reported history of sulfa allergy had significantly more ocular adverse reactions after the initiation of any of the topical antiglaucoma medications when compared to those patients with no reported allergies. Patients with a self-reported sulfa allergy and patients who self-reported other, nonsulfa-related allergies had similar rates of adverse reactions to most of the topical medications. The patients reporting a sulfa allergy who used topical CAIs did not have more adverse reactions compared with patients who reported having other, nonsulfa-related allergies who used topical CAIs. Self-reported sulfa-allergic patients had similar rates of adverse reactions to topical CAIs compared with topical prostaglandin analogues.

It may be safe to use a topical CAI in patients who report a history of a sulfa allergy. Patients with medication allergies of any kind may be more likely to develop allergic reactions to other, unrelated drug classes.