Document resource
Background and Importance Brimonidine is a selective α 2-adrenergic receptor agonist that lowers intraocular pressure by inhibiting aqueous humour production and increasing uveoscleral outflow. It is commonly prescribed for glaucoma management. According to its data sheet, reported adverse effects include allergic conjunctivitis, ocular hyperaemia, and blurred vision. However, pupillary seclusion has not been previously described. Hospital pharmacovigilance systems play a key role in identifying and reporting such unexpected adverse reactions to improve patient safety.Aim and Objectives To analyse the possible causal relationship between pupillary seclusion and chronic brimonidine use, and to describe the multidisciplinary approach implemented for its management.Material and Methods We conducted a retrospective study of an 87-year-old man with glaucoma who had been using brimonidine since 2023. Data were extracted from the electronic clinical history system (Diraya). The safety profile was reviewed in the DS, and the Orange algorithm was applied to assess causality between brimonidine and the observed adverse effect. The algorithm consists of 10 questions with three possible responses: Yes (+1), No (0), and Unknown (0). Based on the final score, causality is categorised as: ≥9 = definite, 5–8 = probable, 1–4 = possible, 0 = doubtful ADR.Results In May 2024, the patient presented to the ophthalmologic emergency department with decreased visual acuity in his left eye. Extensive synechiae were observed on physical examination, and he was diagnosed with pupillary seclusion. Brimonidine was immediately discontinued, and a YAG iridotomy was performed, successfully restoring visual acuity. The hospital pharmacy was consulted to evaluate the probability of an adverse drug reaction. Their investigation, including a review of the literature and the DS, found no previously reported cases. Given the high likelihood of an adverse effect, the event was reported to the PS. The patient scored 5 points on the Orange algorithm, indicating a probable causal relationship with brimonidine.Conclusion and Relevance This case demonstrates a rarely reported adverse reaction to brimonidine, pupillary seclusion, highlighting the importance of multidisciplinary management for early detection and reporting of adverse effects. This integrated approach is essential for accurately establishing causality and ensuring optimal patient safety.Conflict of Interest No conflict of interest