How can a Medicare beneficiary apply for Medicaid as well?

You might also talk with your doctor about changing the prescription to one that Medicare covers, if that's the problem. A pharmacist actually did this for my FIL on his behalf when it was discovered the Medicare didn't cover it. The doctor quickly prescribed something similar and covered.

Medicaid is a program funded by federal and state money, administered by your state. Look up your state or county welfare office and contact them for an application. Another solution, talk to your pharmacists or the company that makes your drug to find out about low cost or free medication provided by the manufacturer. Also, see if your doctor will allow you to use a generic medication ot brand name. Ask doc for free samples. Find out if there is a research trial in your area where your treatment would be covered. Good luck.