Medicare Part B is a component of the broader Medicare program, providing health insurance for individuals aged 65 or older, and certain younger people with disabilities or specific conditions. This part of Medicare primarily covers outpatient medical services and supplies, including specific types of drugs that meet particular criteria.
What Qualifies a Drug for Medicare Part B
A drug generally qualifies for Medicare Part B coverage if it is administered by a medical professional in an outpatient setting. This includes drugs given in a doctor’s office, hospital outpatient department, or through a home health agency. The drug must typically not be self-administered and must be medically necessary for the diagnosis or treatment of an illness or injury. For example, if an injection is usually self-administered, it may not be covered by Part B, but if administered as part of a physician’s service, it might be. Part B also covers drugs incident to a physician’s service or furnished for use with covered durable medical equipment.
Common Categories of Part B Covered Drugs
Medicare Part B covers a limited range of specific drug categories, often including injectable or infusible medications administered in a clinic or hospital setting. These include:
Chemotherapy drugs received in a doctor’s office or outpatient clinic.
Certain vaccines, such as influenza, pneumococcal, hepatitis B for at-risk individuals, and COVID-19 vaccines.
Drugs used with durable medical equipment, like medications administered via a nebulizer.
Immunosuppressive drugs for transplant patients, especially if Medicare helped pay for the organ transplant.
Some oral anti-cancer drugs, oral anti-emetic drugs, erythropoietin for end-stage renal disease, and blood clotting factors for hemophilia.
Understanding Your Costs for Part B Drugs
After meeting the annual Part B deductible ($257 in 2025), individuals typically pay 20% of the Medicare-approved amount for most Part B-covered drugs. There is no annual limit on out-of-pocket costs for beneficiaries in traditional Medicare. Coinsurance may be less than 20% for certain drugs if their prices have risen faster than inflation, as per the Inflation Reduction Act. Supplemental insurance plans, such as Medigap or Medicare Advantage plans, may help cover these costs. Medicare Advantage plans have their own cost-sharing structures but cannot charge more than 20% coinsurance for in-network Part B drugs like chemotherapy.
Part B Drugs Versus Part D Drugs
Distinguishing between drugs covered by Medicare Part B and Part D is important. The fundamental difference lies in how and where the drug is administered. Part B primarily covers drugs administered by a healthcare provider in an outpatient setting, such as injections or infusions received in a doctor’s office or hospital. In contrast, Medicare Part D, which is prescription drug coverage offered by private plans, generally covers drugs individuals pick up at a pharmacy and administer themselves at home, typically oral medications.
However, some drugs can fall under either Part B or Part D depending on specific circumstances. For example, certain oral cancer drugs may be covered by Part B if they are the oral form of an injectable drug, while other oral chemotherapy drugs might fall under Part D. Insulin used with an external insulin pump may be covered under Part B as durable medical equipment, whereas most other insulin products are covered under Part D. If a self-administered drug is needed in a hospital outpatient setting, Part B generally does not cover it, and the patient may need to pay upfront and seek reimbursement from their Part D plan. This distinction highlights the importance of understanding specific drug coverage rules.