Purpose: To report a case of transient, bilateral cotton spots after initiation of macitentan, an endothelin receptor antagonist used for the treatment of pulmonary arterial hypertension.
Methods: Case report.
Results: A 76-year-old woman with WHO Class IIIb pulmonary arterial hypertension was referred for evaluation of bilateral cotton-wool spots 1 week after starting macitentan therapy. The patient was asymptomatic and visual acuity was 20/25 in each eye. Fluorescein angiography and optical coherence tomography were completed. Given lack of symptoms and alternative treatment options, the patient was observed closely. The cotton-wool spots resolved 8 weeks after presentation and visual acuity remained stable at 20/25. Throughout the observation period, average mean arterial pressure was within normal limits at 84.8.
Conclusion: In patients using endothelin receptor antagonists, medication side effect should be considered in the differential diagnosis of cotton-wool spots.