Acute unilateral NAION following tirzepatide therapy: a case report

Introduction: Dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists, such as tirzepatide, have significantly advanced the management of type 2 diabetes mellitus and obesity. However, emerging safety signals have raised concerns regarding rare ocular adverse events. Case presentation: We report a case of an obese patient undergoing treatment with tirzepatide who presented with progressive, painless visual loss in the left eye two weeks after symptom onset. Four weeks prior to presentation, she had initiated tirzepatide therapy for weight reduction at a dose of 15 mg once weekly without standard dose titration. Best-corrected visual acuity was 20/20 in the right eye and counting fingers at 1 meter in the left eye. Fundus examination revealed hyperemic optic disc oedema with peripapillary flame-shaped haemorrhages. Automated perimetry demonstrated a central scotoma. MRI of the brain and orbits excluded intracranial pathology and showed no optic nerve enhancement. Intravenous methylprednisolone was administered, after which visual acuity improved to 20/40. Conclusion: Regulatory and pharmacovigilance data suggest that NAION may represent a very rare adverse event associated with GLP-1 receptor agonists, with observational studies indicating a possible association for tirzepatide, although absolute risk appears low and causality remains unproven. While the relationship between dual GIP/GLP-1 receptor agonists and NAION remains controversial, clinicians—particularly ophthalmologists—should remain vigilant and consider this potential risk when evaluating the benefit–risk profile for individual patients.