Open Enrollment: What to Know About Prescription Benefits Before You Choose a Plan

The numbers for 2027 are notable. The average premium for stand-alone Part D drug plans will increase 50%, rising from $38.72 to $58.20, a cost shift that directly affects the 83% of enrollees who don't qualify for financial assistance. At the same time, the total number of available stand-alone plans will fall 12%, from 360 to 316.

Both changes carry real consequences at the pharmacy counter. Higher premiums and fewer plan choices mean that a plan selected last year may no longer be the most cost-effective option for your prescriptions this year. This article covers what to examine across open enrollment health plans, formularies, drug tiers, cost structures, and pharmacy networks, and where Inside Rx fits in as a resource for additional savings on thousands of medications.

What to Review Before Open Enrollment Starts

Two things need to be in order before any plan comparison begins: your enrollment window and your current medication list. Coverage type determines which schedule applies, and each schedule has firm cutoff dates. Missing the correct window can lock you into an existing plan, regardless of whether it still covers your prescriptions at a reasonable cost, for the full following year.

Check enrollment dates for employer, Marketplace, or Medicare coverage

Each coverage type runs on its own calendar:

• Employer plans: Open enrollment typically occurs in the fall, but the exact dates are set by each employer individually. Contact your HR department to confirm the window.
• Marketplace (ACA) coverage: Open Enrollment runs from November 1 through January 15. Selecting a plan by December 15 starts coverage January 1; enrolling between December 16 and January 15 moves the start date to February 1.
• Medicare: The annual enrollment period runs October 15 through December 7, with changes taking effect January 1. Enrollees affected by a natural disaster may qualify for an extension through December 31 by calling 1-800-MEDICARE.

December 15 functions as the critical marker for most enrollees, it is the last date to select a plan without a gap before January 1 coverage begins.

List your medicines, doses, and refill needs

Before pulling up any plan's formulary, write out every prescription currently being taken. Record the exact drug name, dosage strength, and refill frequency. That list becomes the direct reference point when checking each plan for coverage and having it on hand prevents errors when working against enrollment deadlines.

Read your current plan's notice of changes Medicare Advantage and Part D enrollees receive an Annual Notice of Change (ANOC) from their insurer by September 30. The document typically arrives in the second half of September and presents a direct comparison of current-year plan details against what takes effect next year. It covers changes to premiums, deductibles, copays, drug tiers, and pharmacy networks.

Insurers also distribute an Evidence of Coverage (EOC) around the same time, a more detailed document that outlines the full scope of covered services. Both documents warrant careful review. Formularies, cost structures, and network arrangements can shift from one year to the next, and a plan that was the right fit in a prior year may no longer be. Staying enrolled without reviewing these documents carries real financial risk.

Check How Each Plan Covers Your Prescriptions

With your enrollment window confirmed and your medication list ready, the next task is verifying how each plan covers the specific drugs you take. Every plan maintains its own formulary, an official list of covered medications, and a drug not on that list is typically an out-of-pocket expense, regardless of how long you've been taking it.

Find each medicine on the plan's formulary

Search for each medication individually. Formularies shift throughout the year, and a drug covered under a previous plan may not appear on a new one. To check coverage, visit the insurer's website, review your Summary of Benefits and Coverage, call the insurer directly, or examine any mailed plan materials. Running through your full medication list this way, rather than assuming continuity, is the most reliable method before finalizing any open enrollment health plan selection.

Understand drug tiers and covered alternatives

Plans assign covered drugs to numbered tiers, and the tier determines your cost share. Lower tier numbers correspond to lower out-of-pocket costs. Most plans organize tiers from generic drugs at the lowest cost, through preferred brand drugs (brand-name medications without a generic equivalent), to non-preferred drugs, and up to specialty drugs for complex or chronic conditions. A medication sitting in a high tier warrants a conversation with your prescriber, a covered alternative in a lower tier may be clinically appropriate and meaningfully cheaper.

Check prior authorization, step therapy, and quantity limits

Three plan-level restrictions affect how and when a covered drug can be dispensed. Prior authorization requires the plan to approve a specific medication before covering it. Step therapy requires a patient to try a lower-cost alternative first; only after that trial can the plan approve a newer or higher-cost option. Quantity limits cap how much of a drug can be dispensed at a given time or how frequently a refill is allowed. All three can apply to the same medication, so verifying these conditions upfront prevents delays at the pharmacy.

Confirm coverage for specialty drugs

Specialty drugs treat conditions such as cancer, rheumatoid arthritis, and multiple sclerosis; many are biologics derived from living organisms. The category has grown substantially, only 10 specialty drugs existed in 1990, compared with more than 400 today, and they account for the majority of drug spending despite being used by a small share of patients.

How a specialty drug is administered determines which benefit covers it. Self-administered pills or injections typically fall under the pharmacy benefit; treatments administered at a clinic generally fall under medical benefits instead. Most plans place specialty drugs in a separate tier with either a percentage-based cost or a flat copay that can reach several hundred dollars per fill. Medicare Part D caps specialty drug out-of-pocket spending at $2,000 for 2025, and manufacturer assistance programs may reduce costs further.

Check pharmacy networks and mail-order options

Not every pharmacy accepts every plan. Confirm your regular pharmacy is in-network before enrolling, since using an out-of-network pharmacy typically means paying more or paying in full. For medications taken on an ongoing basis, mail-order delivery often reduces per-fill costs and eliminates the need for monthly pharmacy trips.

Where plan coverage leaves gaps, Inside Rx provides savings on thousands of medications, a practical option for managing costs as you work through your healthcare insurance open enrollment decision.

Compare Prescription Costs Across Open Enrollment Health Plans

A plan's formulary tells you what's covered. The cost structure tells you what you'll actually pay. These are separate calculations, and the plan with the lowest monthly premium frequently produces the highest total annual spend once deductibles, copays, and coinsurance are factored in.

Add premiums and expected drug costs for the year

Total yearly costs equal your monthly premium multiplied by 12, plus deductibles, copays, and coinsurance for the care you expect to use. Metal tier levels matter here: bronze and silver plans typically cover 60% to 70% of total costs, while gold and platinum plans cover 80% to 90%, with the enrollee paying less out-of-pocket at the point of care.

Check drug deductibles, copays, and coinsurance

Some plans apply a single combined deductible to both medical and prescription costs; others set a separate deductible specifically for medications. For Medicare drug plans, that deductible cannot exceed $590. Generic drugs frequently carry copays as low as $15. Coinsurance, typically around 20% of the plan's allowed amount, applies after the deductible is met.

Understand which drug costs count toward out-of-pocket limits

Copays, deductibles, and coinsurance generally count toward your out-of-pocket maximum. For Marketplace plans in 2026, that cap is $10,600 for individuals and $21,200 for families. Premiums, out-of-network care, and any medications not covered by the plan do not count toward that ceiling.

Check eligibility for drug cost assistance

Premium tax credits are available to households earning between 100% and 400% of the federal poverty line. Enrollees earning up to 250% of the poverty line may also qualify for cost-sharing reductions, though those reductions apply exclusively to Silver plans. Where coverage gaps remain, Inside Rx provides savings on thousands of medications as an additional cost management option.

Choose a Plan and Prepare for Your First Refill

Confirming formulary coverage is one step; completing enrollment correctly and preparing for your first prescription fill is another. Both matter.

Resolve coverage questions with the insurer and your prescriber

Before submitting any enrollment paperwork, contact the insurer directly to confirm whether your medications require prior authorization or step therapy, and what happens if a drug is non-formulary, whether that means a formal appeal or full out-of-pocket payment. Your prescriber is also a useful resource at this stage; they can identify a covered therapeutic alternative or submit the documentation an insurer requires to approve your current medication.

Complete enrollment and confirm the coverage start date

Plan enrollment can be completed through the insurer's website, by mail, by fax, or by calling 1-800-MEDICARE. Medicare applicants will need their Medicare number, Part A or Part B coverage start date, date of birth, mailing address, and payment details. Those switching Medicare Advantage plans should enroll in the new plan first and leave the existing one in place; the prior coverage terminates automatically when the new plan takes effect. For Marketplace coverage, the enrollment deadline determines when benefits begin, plans selected by December 15 start January 1, while enrolling between December 16 and January 15 pushes the start to February 1.

Ask about transition refills if your medicine is not covered

When a prescription isn't covered at the start of a new plan year, request a temporary supply from the insurer while an exception or alternative is arranged. For Medicare enrollees who paid out of pocket for covered prescriptions before drug coverage began, the LI NET Program may reimburse a portion of those costs. Inside Rx can also serve as a stop-gap, providing savings on thousands of medications while coverage details are finalized.

Conclusion

Formularies shift, premiums change, and plans that covered your medications last year may not offer the same terms this year. Confirming drug coverage, reviewing tier placements, and calculating total annual costs, not just monthly premiums, before enrolling reduces the risk of unexpected out-of-pocket expenses at the pharmacy. Your medication list, the Annual Notice of Change, and a side-by-side cost comparison are the three tools that matter most in this process. Where plan coverage leaves gaps, Inside Rx provides savings on thousands of medications as an additional option for managing prescription costs.

References

• https://www.aarp.org/medicare/open-enrollment/
• https://www.healthcare.gov/quick-guide/dates-and-deadlines/
• https://www.medicare.gov/health-drug-plans/open-enrollment
• https://www.ncoa.org/article/5-things-to-check-during-medicare-open-enrollment/
• https://accessiahealth.org/preparing-for-open-enrollment-what-you-need-to-know/
• https://www.medicare.gov/basics/forms-publications-mailings/mailings/costs-and-coverage/upcoming-plan-changes
• https://www.medicareresources.org/glossary/annual-notice-of-change/
• https://www.uhc.com/news-articles/medicare-articles/medicare-plan-annual-notice-of-change-what-to-look-for
• https://www.ncoa.org/article/what-is-a-medicare-annual-notice-of-change-anoc/
• https://www.medicare.gov/health-drug-plans/part-d/what-drug-plans-cover
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• https://www.healthcare.gov/choose-a-plan/your-total-costs/
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• https://www.cigna.com/knowledge-center/what-is-an-out-of-pocket-maximum
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• https://www.medicare.gov/publications/11109-your-guide-to-medicare-prescription-drug-coverage.pdf
• https://www.medicarerights.org/fliers/Medicare-Advantage/Private-Health-Plan-Questions.pdf?nrd=1