Prescribing carbonic anhydrase inhibitors to patients with "sulfa" antibiotics allergy: do we dare?

To evaluate if provider characteristics affect attitude toward carbonic anhydrase inhibitors (CAI) prescription for patients with history of sulfonamide antibiotic (SA) hypersensitivity.

A survey querying providers' attitudes toward CAI prescription in hypothetical patients with prior SA hypersensitivity was distributed to four ophthalmology and optometry organizations. Logistic regression was used to assess the relationship between avoiding CAI and profession, specialty, organizational affiliation, and years in practice.

Of 250 respondents, 27% and 52% would avoid topical and oral CAI, respectively, in patients with prior SA rash and/or urticaria. >90% would avoid oral CAI in patients with prior severe SA hypersensitivity. Respondents with >10 years in practice were more likely to avoid oral CAI in patients with prior SA rash and/or urticaria than those with ≤10 (OR 2.27, p = 0.002). Respondents affiliated with non-glaucoma organizations were more likely to avoid oral CAI in patients with prior SA rash and/or urticaria than those affiliated with glaucoma organizations (p = 0.03). Providers without glaucoma training were more likely to avoid topical CAI in patients with prior SA rash and/or urticaria (p = 0.004) and anaphylaxis (p = 0.01) than glaucoma-trained providers.

Despite no supporting evidence, a significant number of respondents would avoid CAI in patients with prior SA hypersensitivity. Respondents without glaucoma training, no affiliation with a glaucoma organization, and >10 years in practice are more likely to avoid CAI in patients with type I SA hypersensitivity. Providers should be informed of the low cross-reactivity risk between CAI and SA so more patients may benefit from these drugs.