PURPOSE: Relief of post-surgical ocular redness can be achieved with topical ophthalmic vasoconstrictors. Adverse events (AEs) associated with sustained use of α-adrenergic receptor (AR) agonists include tachyphylaxis and rebound redness. Here we investigate whether brimonidine tartrate ophthalmic solution (0.025%; BTOS) is associated with such AEs.

METHODS: BTOS is a selective α2-AR agonist, with a relative binding affinity for α2 vs α1 of ~1000:1, exhibiting potent vasoconstrictor activity at concentrations as low as 0.025%. In contrast, other approved topical ophthalmic vasoconstrictors are either α1-AR agonists (e.g., tetrahydrozoline) or mixed α1/α2-AR agonists (e.g., naphazoline/oxymetazoline), with α2:α1 binding affinities of around 2:1 or 5:1, respectively. We reviewed pharmacovigilance data for BTOS covering a period (05/2018–12/2022) when 49.9 million units were sold. AE reports that may be associated with overuse and subsequent increased redness (dependent on MedDRA coding) were noted.

RESULTS: In total, there have been 341 reports of ocular hyperaemia, 60 reports of rebound effect and 9 reports of symptom recurrence. In addition, there were 503 reports of drug ineffective (and 6 of drug effect less than expected), 423 reports of therapeutic product effect incomplete, 71 reports of effect decreased and 1 report of effect shortened. While it is important to note that reports of AEs do not establish causality, and the voluntary nature of self-reporting can result in an underestimation of the true incidence, this post-marketing real-world AE profile provides insight into the longer-term safety of BTOS, with few reports of tachyphylaxis and rebound redness.

CONCLUSION: The specific action of brimonidine on α2-ARs is hypothesised to reduce the potential for AEs associated with overuse and contribute to a distinct safety profile.