Medicare Part D plans in San Antonio.

What is Medicare Part D?

Medicare Part D is prescription drug coverage offered by private insurance carriers approved by Medicare. It helps pay for the cost of prescription medications — including brand-name and generic drugs, vaccines, and certain medical supplies like insulin.

Part D isn't automatic when you sign up for Medicare. You have to actively choose and enroll in a Part D plan unless you have other "creditable" prescription drug coverage (like through a former employer or VA benefits).

How Medicare Part D works

You pay a monthly premium for the plan plus deductibles and copays/coinsurance when you fill prescriptions. Each Part D plan has its own:

• Formulary — the list of drugs the plan covers, organized into tiers (Tier 1 generic = cheap; Tier 4 specialty = expensive)
• Network pharmacies — preferred pharmacies usually have the lowest costs; standard pharmacies cost more; out-of-network may not be covered at all
• Coverage rules — some drugs require prior authorization, step therapy (try cheaper drug first), or have quantity limits

This is why the right Part D plan for you depends entirely on which medications you take. A plan that's perfect for someone on Eliquis and Metformin might be a disaster for someone on Trulicity and Jardiance.

The four phases of Part D coverage

Part D has a slightly confusing benefit structure — but you don't need to understand every detail to use it. Here's the simple version:

1. Annual Deductible

Some plans have a $0 deductible. Others charge up to the federal maximum ($590 in 2026). You pay the full negotiated cost of drugs until you hit the deductible. Note: many plans waive the deductible on Tier 1 and Tier 2 drugs.

2. Initial Coverage Phase

After meeting the deductible, you pay a copay (flat amount like $5) or coinsurance (percentage like 25%) for each prescription. This continues until your combined spending (what you and the plan pay) reaches the initial coverage limit.

3. Coverage Gap ("Donut Hole")

Once you've spent enough in the initial phase, you enter the coverage gap. Important update for 2026: due to the Inflation Reduction Act, the donut hole has been substantially restructured. Out-of-pocket costs for Part D are now capped at $2,100 annually across all phases combined. This is a major improvement over previous years.

4. Catastrophic Coverage

Once you hit the annual out-of-pocket cap, you pay $0 for all covered drugs for the rest of the calendar year. The cap resets January 1.

Why your specific prescriptions matter so much

Most agents will quote you the lowest-premium Part D plan and call it a day. That's lazy and often costs you thousands per year.

Here's a real example: a San Antonio retiree taking three common medications. Two equally "cheap-looking" plans:

Cost Component	Plan A ($8/mo premium)	Plan B ($35/mo premium)
Annual premium	$96	$420
Deductible	$590	$0
Drug 1 (brand)	Tier 4 — $90/mo	Tier 2 — $15/mo
Drug 2 (generic)	Tier 2 — $8/mo	Tier 1 — $0/mo
Drug 3 (specialty)	Not on formulary	Tier 3 — $47/mo
Annual total	$2,206 + uncovered drug	$1,164

The "cheaper" plan costs $1,000+ more per year for this person. That's why Mark runs your specific medications against every plan in your ZIP — not just by premium.

What Mark checks when comparing Part D plans for you

• Formulary coverage — is every drug you take actually covered, or will you have to switch medications?
• Tier placement — what tier is each drug on, and what's the copay?
• Pharmacy network — is HEB, CVS, Walgreens, or your favorite pharmacy preferred or standard?
• Mail-order options — many plans give 3-month supplies through mail-order at lower cost
• Restrictions — does any drug require prior authorization, step therapy, or have quantity limits?
• Annual total estimate — what will the real year cost you, all in, with your real prescriptions?

Part D and Medicare Advantage

Most Medicare Advantage plans bundle Part D into the plan ("MA-PD" plans). If you enroll in an Advantage plan with drug coverage, you cannot also enroll in a standalone Part D plan — Medicare will automatically disenroll you.

If you enroll in a Medicare Advantage plan without drug coverage (rare, but they exist for VA beneficiaries and others), you generally can't add a standalone Part D plan either. Most people who want both choose an MA-PD plan from the start.

When can you enroll in Part D?

Initial Enrollment Period (IEP)

The 7-month window around your 65th birthday. Same window as Part A and B enrollment.

Annual Enrollment Period (AEP)

October 15 – December 7 every year. The main window to change Part D plans. Changes effective January 1.

Special Enrollment Periods (SEPs)

Triggered by qualifying events: moving, losing creditable coverage, qualifying for Extra Help, etc.

Extra Help (Low-Income Subsidy)

If your income and assets are below certain thresholds, you may qualify for Extra Help — a federal program that pays most or all of your Part D premiums, deductibles, and copays. Mark will check whether you qualify and walk you through the application. Many people who could qualify never apply because nobody told them about it.

2026 Extra Help eligibility (approximate)

• Income: Up to ~$23,475 individual / ~$31,725 married couple (150% of Federal Poverty Level)
• Resources: Up to ~$17,600 individual / ~$35,130 married couple (savings, investments — excluding home and one car)

If you're close to these limits, it's worth applying. Mark can help you start the application.

Major Part D carriers in San Antonio

Mark represents multiple Part D carriers and compares plan options across all of them. Common standalone Part D carriers in Texas:

Annual review — why it matters every year

Part D plans change their formularies, tier placements, premiums, and pharmacy networks every year. The plan that was perfect for you in 2025 might be a bad fit in 2026 if:

• Your medications moved to a higher tier
• A drug got removed from the formulary entirely
• The plan changed which pharmacies are "preferred"
• You started a new medication
• A cheaper plan from a different carrier now covers all your drugs better

Mark reviews every client's Part D plan every year during AEP automatically. You don't have to ask. If a better plan exists for next year, he tells you. If your current plan is still best, he tells you that too.