Coordination of benefits is the process insurers use to determine which plan pays first when a person is covered under more than one insurance plan at the same time. The coordination process is governed by state or federal law, and ensures that your health care provider is not overpaid. When using your prescription drug plan, you should always inform your doctor or pharmacist if you are covered by more than one insurance plan. This will help your provider know which plan to bill in order to comply with your coverage guidelines. You should not try to conceal information about additional coverage in order to lower the payments you personally make because this might be viewed as an attempt to commit fraud.