SCIENTIFIC REPORT Do selective topical b antagonists for glaucoma have respiratory side effects?

Background/aims: Topical b antagonists are prescribed for glaucoma in approximately 500 000 people in the United Kingdom. The authors have previously shown that topical b antagonists are associated with an excess incidence of airways obstruction. They examined whether selective topical b antagonists are associated with excess airways obstruction. Methods: A historical cohort study was performed to determine the incidence of airways obstruction in subjects with no previous history of airways obstruction, following treatment with topical b antagonists for glaucoma for the period 1993–7. Cases were defined as having received a first prescription of a drug specifically used in the management of airways obstruction. Results: For selective topical b antagonists 12 of 324 treated subjects developed airways obstruction, compared with 112 of 9094 controls (adjusted hazard rate 3.0 (95% confidence interval (95% CI) 1.6 to 5.4)). For non-selective topical b antagonists, the corresponding figures were 69 of 2321 subjects compared with the same control group (adjusted hazard rate 2.2 (1.6 to 3.0)). There was no significant difference between groups (p = 0.47, x), both being associated with a significantly increased risk of airways obstruction. Conclusion: Selective topical b antagonists do appear to have an excess risk of airways obstruction in this population setting and should be subject to the same prescribing caveats as unselective topical b antagonists.