​A drug formulary is a list of prescription drugs that your health plan can help you pay for. Generic and brand-name drug lists provide effective medications at the cheapest possible cost.

Here are five things to know about the drug formulary: 

​Medicare Advantage plans are optional alternative health care insurance to the original Medicare. Medicare Supplement plans can only be consumed together with the original Medicare plan. Such information is the basic difference between Medicare Advantage and Medicare Supplement plans. Below are the other differences between the two Medicare insurance coverages:

​Prescription or outpatient drugs are not covered by Medicare Part A and B. This is why Medicare Part D was created. This supplement insurance covers the costs of prescription drugs. Part D coverage has a list of generic and brand names for drugs that are eligible for coverage. These formulas change from year to year. Some Medigap may require authorization before a drug could be prescribed.

​Medicare Supplement Plans or Medigap helps in filling some of the gaps in the Original Medicare plan. Although the Original Medicare pays for almost all of the costs, there are still holes in Medicare's healthcare services coverage. Included in the Medigap coverage are deductibles, coinsurance, and copayments.