Dual eligibles could lose access to some of their medicines when their Medicaid drug coverage transfers to Medicare under the new drug benefit, preliminary government study findings say.

The Government Accountability Office found that CMS’ plan does “not ensure that dual-eligible beneficiaries can immediately obtain necessary drugs.” Also, auto enrolling these beneficiaries could throw off their drug regimen, the report said.

Moreover, if coverage is not arranged for dual eligibles in the form of a drug plan, they could encounter problems paying retail price for the drugs upfront.

Findings for the report can still be changed. The GAO is expected to edit the final report to include steps the Centers for Medicare & Medicaid Services is taking to ensure that dual-eligibles receive the drugs they need.