OBJECTIVES: To examine use of donepezil 23 (D23) in a real-world setting among medicare and commercially insured patients. METHODS:   Patients diagnosed with Alzheimer’s disease (ICD-9-CM 331.xx), ≥ 50 years old initiating D23 (index date) during 7/1/2010-5/31/2011 with 3 months pre- and 6 months post-index eligibility were identified from Humana claims database (medicare 60%, commercial 40%).  Demographic characteristics were measured pre-index.  Clinical characteristics were measured pre- and post-index. Patients were categorized into 2 cohorts: continued (CON), discontinued (DIS). Discontinuation was defined as a gap of ≥ 30 days post-index. Outcomes assessed: time on 10 mg donepezil (pre-index), AD-related healthcare resource utilization and costs, length of therapy and time to discontinuation and use of memantine. RESULTS: A total of 479 patients were identified: 204 CON, 275 DIS. Mean age [SD] was less for CON (78.8 [7.5] v 80.5 [7.3]; p=0.012) with no differences in comorbidity scores (0.37). 59.3% of CON patients, and 67.3% of DIS patients were female (p=0.073). Over half used memantine, with greater percentage of CON patients using memantine compared to DIS patients pre-(68.1% v 52.0%; p=0.0004) and post-index (77.0% v 58.9%; p<0.0001).  More CON patients had ≥ 60 days of pre-index 10 mg donepezil use (62.2% v 45.4%; p=0.0003). More DIS patients had an ER visit (10.2% v 3.9%; p=0.035) compared to CON patients. Length of stay in a skilled nursing facility (SNF) (1.3[5.4] v 0.9[5.3]; p=0.044) was longer on average for DIS patients.  DIS patients had higher ER AD-related costs compared to CON patients ($135[680] v $53[343] p=0.011). CONCLUSIONS:   Significantly less AD-related healthcare utilization and costs were associated with continued D23 use compared to patients who discontinued. More patients who continued therapy  had > 60 days on donepezil 10mg before starting the D23 treatment vs DIS patients, suggesting patients receive > 60 days of 10 mg prior to initiating D23.