Branch retinal artery occlusion in a 49-year-Old woman taking phentermine.

Purpose: This report describes the presentation of a 49-year-old woman with a branch retinal artery occlusion of the right eye in the setting of taking phentermine, a commonly used weight loss medication. Observations: A 49-year-old woman presented with acute painless vision loss in her right eye and was found to have a branch retinal artery occlusion after taking prescribed dosages of phentermine for weight loss therapy. Fundus examination revealed retinal whitening in the distribution of the superior temporal branch retinal artery, and spectral domain optical coherence tomography demonstrated macular edema. Systemic evaluation was negative for cardiovascular, infectious, or autoimmune etiologies. Based on the retinal findings, the patient was diagnosed with phentermine associated branch retinal artery occlusion. She was followed for nine years with no further complications and her vision remained stable in the right eye. Conclusions and Importance: This case highlights that phentermine, a commonly used weight loss medication, could be associated with ischemic retinopathies. Thus, clinicians should be aware that retinal vascular occlusions may not only occur in those who use recreational amphetamines but also in patients taking the prescribed dosages of a weight loss medication like phentermine.