Nearly 2 million low-income Medicare participants could be switched to different insurance plans for their prescription drug coverage next year.

Millions more will have to shop around if they want to avoid double-digit increases in their monthly premiums.

The reassignment of the poorest beneficiaries and the higher premiums for many others are just two reasons why seniors and the disabled may want to look into other plans as the Medicare drug benefit enters its third year.

Under the drug benefit, Medicare subsidizes insurance plans that cover an enrollee's prescription drug buys. The government pays insurers extra for covering the very poor.