Levodopa/carbidopa associated autoimmune hemolytic anemia is a rare pharmacologic side effect that poses a dilemma in management of advanced Parkinson’s disease, where dopaminergic responsiveness is critical to function. We present a rare case of autoimmune hemolytic anemia (AIHA) induced by levodopa in a patient with Parkinson’s disease (PD).
A 75-year-old female with PD, diagnosed in 2018- previously responsive to levodopa 800mg/day, developed symptomatic macrocytic anemia in June 2025 after several years of carbidopa/levodopa use. She was not taking any other medications at that time. Work-up showed hemoglobin nadir 9.1–9.4 g/dL, reticulocytosis (up to 12.5%), indirect hyperbilirubinemia (to 1.7 mg/dL), elevated LDH (to 273 U/L), very low haptoglobin (<30 mg/dL), and a direct antiglobulin (Coombs) test positive for IgG and C3—consistent with warm AIHA.
Carbidopa/levodopa was discontinued and high-dose intravenous steroids initiated with transition to oral prednisone taper as outpatient. The patient's hemoglobin subsequently improved to 11 g/dL with gradual biochemical recovery. Alternative PD agents were ineffective or not tolerated and the patient experienced rapid motor decline (persistent OFF state, falls, severe bradykinesia, postural instability) with loss of independence in Activities of Daily Living(ADLs).
Given the disabling motor decline following levodopa discontinuation and limited response to alternative agents, the patient was considered for deep brain stimulation candidacy. A cautious levodopa re-challenge under low-dose prednisone and close monitoring was reserved as an intervention of last resort.