by: Eric Widera ( @ewidera ) There are two main drug classes use to treat Alzheimer's disease, cholinesterase inhibitors (ChEIs) and the NMDA-antagonist memantine. Both have shown statistically significant improvements in outcomes for patients with AD, but the clinical significance of these benefits is marginal at best. Furthermore, these benefits vary with disease severity, with ChEIs showing benefit from mild to servere dementia, and memantine showing benefit only in moderate to severe disease. So how closely does clinical practice mirror the evidence behind these drugs? A new study in JAGS suggests that your chances of being started on these drugs is about 50/50, and has less to do with FDA approved indications, and more to do with who you see and where you live. The Study The authors used a national sample of Medicare beneficiaries enrolled in Medicare Part D from 2008 to 2010 and evaluated the frequency of ChEI’s and mematine prescription fills in people with