Medicare Part D

Two Doors to Drug Coverage: What Changes When You Switch

In Downey, many people on Medicare face the same fork in the road: get prescription drug coverage through a stand-alone Part D plan paired with Original Medicare, or get it built into a Medicare Advantage plan. Both paths lead to drug coverage, but they work differently — and moving between them can change more than just your pharmacy card.

Here is a plain-language look at how the two structures compare, and what actually shifts if you switch.

Two structures, one goal

A stand-alone Part D plan is a prescription-only plan you add on top of Original Medicare (Parts A and B). Your medical care stays under the federal Medicare program, and your drug coverage comes from a private insurer that contracts with Medicare.

A Medicare Advantage plan with drug coverage (often called an MA-PD) rolls hospital, medical, and drug benefits into a single private plan. You still have Medicare, but a private insurer manages your benefits, usually through a network of doctors and pharmacies.

Downey is in Los Angeles County, where a wide range of both stand-alone Part D plans and Medicare Advantage plans are offered each year. Plan availability is set at the county level, so two neighbors in the same ZIP code generally see the same menu of options.

What the two paths share

No matter which door you pick, the underlying Part D rules work the same way in 2027:

• The annual out-of-pocket cap on covered drugs is $2,100 in 2026 and $2,400 in 2027.
• The maximum deductible any Part D plan can charge is $615 in 2026 and $700 in 2027 (some plans set it lower).
• The old coverage gap — the "donut hole" — is gone as of 2025. There are now three payment phases instead of four.
• The Medicare Prescription Payment Plan is available on request, letting you spread your yearly drug costs across monthly payments instead of paying big amounts at the pharmacy counter.
• IRMAA surcharges on Part D premiums begin above $109,000 in income for a single filer in 2026.

Those figures come from CMS and apply to any Medicare drug coverage, whether it's stand-alone or built into an Advantage plan.

What actually differs

The pieces around the drug benefit are where the two paths part ways.

How you see doctors. With Original Medicare plus a stand-alone Part D plan, you can generally see any provider in the country who accepts Medicare, with no referrals. Medicare Advantage plans typically use networks (HMO or PPO) and may require referrals or prior authorization.

Extra benefits. Many Medicare Advantage plans include extras like dental, vision, hearing, or fitness benefits. Original Medicare plus stand-alone Part D does not — you would buy those separately or go without.

Premiums and how you pay. With the stand-alone route, you pay the Part B premium plus a separate Part D premium, and often a Medigap premium if you carry one. With Medicare Advantage, you still pay Part B, plus whatever premium the Advantage plan charges (which varies).

Formularies and pharmacies. Every plan — stand-alone or Advantage — has its own drug list (formulary) and preferred pharmacy network. A drug that's covered cheaply on one plan may be tiered differently on another.

What changes if you move between them

Switching isn't just a paperwork change. A few things you should know before making the leap:

• Going from Advantage to Original Medicare + Part D: You get freedom of provider choice back, but you may want a Medigap (Medicare Supplement) policy to help with Part A and B cost-sharing. Outside your initial Medigap open enrollment window, insurers in California can use medical underwriting for most applicants, which may affect whether you qualify.
• Going from Original Medicare + Part D to Advantage: Your medical benefits move under the private plan, so check that your doctors and preferred pharmacies are in-network, and confirm your prescriptions are on the plan's formulary.
• Timing matters. Most people can only switch during the Annual Enrollment Period (October 15 – December 7) for coverage starting January 1. If you're already in a Medicare Advantage plan, the Medicare Advantage Open Enrollment Period (January 1 – March 31) gives you one more chance to change Advantage plans or return to Original Medicare with a Part D plan.

Where to get personalized help

Because the "right" path depends on your doctors, your medications, and your budget, use official sources rather than sales calls:

• Medicare.gov — the Plan Finder lets you compare drug plans and Advantage plans using your own prescription list and pharmacy.
• 1-800-MEDICARE (1-800-633-4227) — available 24/7.
• California's SHIP, called HICAP (Health Insurance Counseling and Advocacy Program), offers free, unbiased one-on-one counseling for Downey residents.