Walgreens is threatening to stop filling Medicaid prescriptions at 64 of its 121 pharmacies in Washington state because of state cuts in payments. Walgreens, the biggest drug-store chain in the country, threatened to pull out of Medicaid programs last year before settlements were reached in Delaware and in Washington state. Because Medicaid's payment rates to doctors are lower than those paid by Medicare and private insurers, lots of docs refuse to take Medicaid patients. The issue will likely become a bigger sore point if the Medicaid umbrella expands, the Wall Street Journal Health Blog reports.