Learn how prescription drug formularies, tiers, and prior authorization work in NC marketplace and Medicare plans — and how to manage your medication costs.
Written by the licensed agents at Health Plans of NC, an insurance agency authorized by Blue Cross and Blue Shield of North Carolina (Blue Cross NC).
A formulary is the official list of prescription drugs covered by your health plan — and understanding it can save you hundreds of dollars a year.
NC marketplace and Medicare plans organize drugs into tiers, with lower tiers costing you less out of pocket.
Prior authorization, step therapy, and quantity limits are common tools insurers use to manage costs — knowing about them helps you avoid surprise denials.
Formularies change each year, so reviewing your plan's drug list during Open Enrollment is one of the most important steps you can take.
If your medication is not on a plan's formulary, you have options: exceptions, appeals, and switching plans during enrollment periods.
A formulary is a list of covered prescription medications that your health insurance plan has agreed to pay for, either fully or partially. Think of it as your plan's approved drug catalog — if your medication is on it, your plan helps pay; if it is not, you generally pay the full retail price.
Every health plan sold in the NC marketplace and every Medicare Part D or Medicare Advantage plan maintains its own formulary. That means two plans sitting side by side in the same premium bracket can cover very different medications at very different costs.
Formularies are not random. Plans negotiate with drug manufacturers and use clinical guidelines to decide which medications to include and at what cost-sharing tier. The goal is to balance broad access with cost control — both for the plan and for enrollees.
Drug tiers determine how much you pay at the pharmacy counter, with lower tiers meaning lower out-of-pocket costs. Most NC marketplace and Medicare plans use a four- to six-tier system.
A typical tier structure looks like this:
Tier 1 — Preferred generics: Lowest copay, often just a few dollars per fill.
Tier 2 — Non-preferred generics: Slightly higher copay than Tier 1 but still affordable.
Tier 3 — Preferred brand-name drugs: Moderate cost-sharing, often a percentage of the drug's cost.
Tier 4 — Non-preferred brand-name drugs: Higher copay or coinsurance.
Tier 5 — Specialty drugs: The most expensive tier, covering complex medications for conditions like cancer, rheumatoid arthritis, or multiple sclerosis.
Where your medication lands on this scale directly affects your monthly spending. A drug that is Tier 1 on one plan could be Tier 4 on another — which is why comparing formularies, not just premiums, matters enormously when choosing health coverage in North Carolina.
Prior authorization (PA) means your doctor must get approval from your health plan before you can fill a prescription. Without that approval, the plan will not pay for the drug.
Insurers use prior authorization to ensure that certain high-cost or high-risk medications are truly necessary and that lower-cost alternatives have been considered first. It is most common for specialty drugs, brand-name medications with generic equivalents, and drugs with significant safety considerations.
The practical impact on you: a delay between your doctor writing a prescription and you being able to pick it up. In most cases your doctor's office handles the PA request, but you should ask upfront whether a new medication requires it. Knowing this before you leave the exam room can prevent frustrating delays.
Step therapy — sometimes called "fail-first" — requires you to try a lower-cost medication before the plan will approve a more expensive one. It is a formal process, not just a suggestion.
For example, if you are prescribed a brand-name arthritis medication, your plan may first require that you try a less expensive generic for a set period. Only if that generic proves ineffective or causes side effects will the plan then approve the brand-name drug.
Step therapy is legal and common in both NC marketplace plans and Medicare Advantage plans. It can slow access to the medication your doctor believes is best, but exceptions can be requested — especially if you have already tried and failed on the step-therapy drug or if starting it would put your health at risk.
ACA marketplace plans and Medicare plans each follow different federal rules, which leads to real structural differences in how their formularies work.
ACA marketplace plans sold on HealthCare.gov for North Carolina must cover at least one drug in each category or class recognized by the United States Pharmacopeia. They are also required to cover all drugs in certain protected classes, such as antidepressants, anticonvulsants, and HIV/AIDS medications, regardless of cost tier.
Medicare Part D and Medicare Advantage plans follow guidelines set by the Centers for Medicare and Medicaid Services (CMS). Medicare plans are required to cover at least two drugs per therapeutic category, and there are six protected drug classes that must be covered with minimal restriction: antidepressants, antipsychotics, anticonvulsants, immunosuppressants, antiretrovirals, and antineoplastics.
The key practical difference: a medication you relied on through an employer plan or marketplace plan may not be covered the same way — or at all — once you move to Medicare. Always cross-check your current medications against any new plan's formulary before you switch, whether you are enrolling in a marketplace plan through HealthCare.gov or a Medicare plan.
Every health plan is required to publish its formulary, and you can access it before you enroll. Here is how to check:
Visit the plan's website and look for a "formulary," "drug list," or "covered medications" link.
Use the NC marketplace tool at HealthCare.gov, which allows you to enter your prescriptions and filter plans based on estimated drug costs.
Call the plan's member services line and ask a representative to confirm coverage and the tier for your specific drug, including the dosage you take.
Ask your pharmacist — they can often look up whether a drug is covered and at what cost under a specific plan's benefit design.
Do not rely solely on the plan summary during enrollment. Formularies change annually, and a drug that was covered this year may move to a higher tier — or be dropped entirely — next year.
A missing drug is not necessarily a dead end. You have several options worth pursuing.
Request a formulary exception. Both ACA marketplace plans and Medicare plans must have a process for requesting an exception. Your doctor submits documentation showing that the excluded drug is medically necessary and that covered alternatives are not appropriate for your condition.
File an appeal. If your exception is denied, you can appeal. Under Medicare, you have the right to an expedited appeal if your condition is urgent. For marketplace plans, the appeals process is outlined in your plan documents and must follow North Carolina state and federal timelines.
Ask about therapeutic alternatives. Your doctor may be able to prescribe a covered drug in the same class that works equally well for you. This is worth a conversation, especially if the non-covered drug is very expensive.
Switch plans during Open Enrollment. If your drug is consistently not covered or is on an unaffordable tier, the best long-term solution may be choosing a different plan that covers it at a lower cost. The ACA marketplace Open Enrollment period for 2027 coverage runs in the fall of 2026, and Medicare's Annual Enrollment Period runs October 15 through December 7 each year.
Specialty drugs — biologics, infused therapies, and other complex medications — represent some of the highest costs in any formulary. They are typically placed on the highest tier and subject to both prior authorization and step therapy.
Under Medicare, the Inflation Reduction Act capped out-of-pocket prescription drug costs for Part D enrollees. This cap provides meaningful relief for people who rely on expensive specialty medications. For 2026 specifically, check with Medicare.gov or a licensed agent for the confirmed annual cap amount applicable to your plan.
For marketplace enrollees in North Carolina, specialty drug costs can vary widely between plans. Some plans use coinsurance rather than a flat copay for specialty drugs, which means your cost is a percentage of the drug's list price — and that percentage can add up quickly for high-cost biologics.
Manufacturer copay assistance programs and nonprofit patient assistance programs can sometimes help offset these costs, but Medicare enrollees must be cautious: some manufacturer coupons cannot legally be applied to Medicare-covered drugs. A licensed agent or your doctor's office can help you navigate what assistance is available to you.
Formularies are updated annually, and changes can significantly affect what you pay. A plan that was a great fit this year may not be next year if your medications have been moved to a higher tier or removed entirely.
During Open Enrollment — whether for the NC marketplace or for Medicare — take these steps before you re-enroll or switch:
Pull your current medication list, including dosages and frequencies.
Look up each drug on every plan you are considering.
Compare not just the tier, but whether prior authorization or step therapy applies.
Factor in your pharmacy preference, since some plans have preferred pharmacy networks with lower cost-sharing.
Spending an hour on this comparison can prevent months of unexpected costs. Health plans available across North Carolina range significantly in how they structure drug coverage, and the plan with the lowest premium is not always the plan with the lowest total cost once you factor in what you spend at the pharmacy.
Federal law provides several important protections for people enrolled in ACA marketplace and Medicare plans in North Carolina.
ACA marketplace plans cannot charge more for drugs in a protected class than they charge for other drugs on the same tier. Medicare plans must have a formal exceptions and appeals process, and decisions must be made within a legally defined timeframe — typically 72 hours for a standard request and 24 hours for an expedited urgent request.
North Carolina also has state-level protections for certain drug categories. If you believe your plan is denying coverage unfairly or applying a formulary restriction incorrectly, you can file a complaint with the North Carolina Department of Insurance (NCDOI) or request an independent external review. The NCDOI Consumer Services Division can guide you through this process.
Understanding these rights puts you in a stronger position to advocate for the medications you need.
This article is for general information and is not insurance or medical advice. Consult a licensed agent.