Part D of the Medicare program, also known as the Medicare prescription drug benefit, is a federal funded and government backed plan to help subsidies the costs of prescription drugs for those already on receipt of Medicare benefits.

Eligibility and options for enrollment

Persons who are already enrolled in both Parts A and B of the Medicare program are eligible to receive prescription drug benefits through two options, both available from a private health insurance provider:  they can join a Prescription Drug Plan (PDP) for drug coverage only or they can join a public Part C health plan that will cover all hospital and medical services covered by Original Medicare at a minimum, and covers extra expenses not covered by Medicare Part A and B including prescription drugs. It is estimated that two-thirds of all Medicare beneficiaries are enrolled directly in Part D or get Part-D-like benefits through a public Part C Medicare Advantage health plan.

Generally, not all drugs are covered at the same out of pocket cost to the beneficiary. This gives participants incentives to choose certain drugs over others.

Medicare recipients must enroll in a Part C or Part D plan to receive the prescription drug benefit. They can enroll directly through the plan’s administrator, or indirectly through an insurance provider. Those who are already on a plan can choose an alternative plan or choose to drop Part C or Part D during a yearly enrollment period or during pre-determined times throughout the year. Other special enrollment circumstances apply, so it is worth contacting a provider to check.


It is important to note that there are certain drugs which are excluded from coverage under a Part D plan. These include:

  • Drugs used in the treatment of anorexiaweight loss, or weight gain
  • Any fertility improving drugs
  • Drugs used for erectile dysfunction
  • Drugs used for cosmetic purposes, such as hair growth simulator
  • Drugs used for the treatment of coughs or the common cold
  • Any prescription vitamins and mineral products which are not prenatal vitamins and fluoride supplements