When your insulin or arthritis medication suddenly costs three times more, it’s not a glitch-it’s a formulary update. Every year, especially starting January 1, 2025, insurance plans and pharmacy benefit managers (PBMs) change which drugs they cover, how much you pay, and sometimes, which exact version of a drug you’re allowed to use. For millions of people on Medicare Part D, these changes aren’t just paperwork-they’re life-altering. You might not get the brand you’ve been taking for years. Instead, you’ll be switched to a generic or biosimilar, often without your doctor’s input. This isn’t about savings for the insurer alone. It’s about whether you can afford to keep taking your medicine at all.
What Exactly Is a Formulary Update?
A formulary is a list of drugs your insurance plan covers. It’s divided into tiers, and each tier has a different price tag. In 2025, the structure is clearer than ever:- Tier 1: Preferred generics-usually $1 to $10 per prescription.
- Tier 2: Non-preferred generics and some preferred brands-around $47.
- Tier 3: Non-preferred brands-$113 on average.
- Specialty Tier: High-cost drugs like cancer treatments or biologics-$113 or 25% coinsurance.
Why Are Insurers Switching You to Generics?
It’s not personal. It’s financial. A single brand-name biologic like Humira can cost over $7,000 a month. Its biosimilar, Amjevita, costs about $3,500. That’s a 50% drop. For insurers managing millions of prescriptions, that adds up to billions in savings. So they move the brand to a higher tier-or remove it entirely-and put the generic or biosimilar in Tier 1. CVS Caremark, one of the biggest pharmacy benefit managers, removed nine specialty drugs from its 2025 formulary and added 18 new ones, including biosimilars like Kanjinti and Trazimera to replace older, more expensive versions. UnitedHealthcare moved Humalog insulin to a higher tier, causing some members to see their copays jump from $35 to $113 overnight. These aren’t mistakes. They’re calculated moves. But here’s the catch: not all generics are created equal. A generic version of a pill like metformin is identical to the brand. But biosimilars-like Amjevita instead of Humira-are highly similar, but not identical. They’re made from living cells, not chemicals. That means even tiny differences can matter for people with autoimmune diseases. Some patients report no change. Others feel worse. And insurers don’t always ask before switching you.Non-Medical Switching: When Your Insurance Decides Your Treatment
"Non-medical switching" is when your insurer changes your drug for cost reasons, not because your doctor thinks it’s better. It’s legal. And it’s rising. According to healthcare attorney Scott Glovsky, cases of non-medical switching jumped 23% in 2024. You could be stable on a drug for years, then get a letter in the mail saying your coverage is changing. No discussion. No trial. Just a new prescription. This is especially dangerous for people with chronic conditions-diabetes, rheumatoid arthritis, Crohn’s disease. A sudden switch can trigger flare-ups, hospital visits, or worse. One Reddit user, "MedicareWarrior87," wrote: "My copay for Humalog jumped from $35 to $113 overnight. I had to choose between insulin and groceries." On the flip side, many people benefit. "ArthriticMom" on HealthUnlocked shared: "I switched from Humira to Amjevita. Saved $450 a month. No difference in how I feel." That’s the ideal outcome. But it shouldn’t be left to chance.
What You Can Do: Four Steps to Protect Yourself
You can’t stop formulary changes. But you can control how they affect you. Here’s how:- Check your formulary between October and December. Every insurer sends out a Summary of Coverage (SOC) by October 1. Don’t ignore it. Look up every medication you take. If your drug moved to a higher tier or was removed, act now.
- Ask your pharmacist. Pharmacists see formulary changes daily. They know what alternatives are covered and which ones have the best track record. Ask: "Is there a generic or biosimilar that’s covered and safe for me?"
- Request an exception. If your drug was removed or moved to a higher tier, your doctor can file a formal exception request. There are two types: standard (takes 72 hours) and expedited (24 hours if your health is at risk). In 2024, 82% of tiering exceptions were approved. But only 47% of requests to reinstate a completely excluded drug got through.
- Use your 30-day transitional supply. If your plan changes your drug, you’re entitled to a 30-day supply of your old medication at the old price. Use that time to get your exception approved or switch safely.
The Big Shift Coming in 2026
2025 is just the warm-up. In January 2026, Medicare Part D plans will be required to cover 10 specific drugs that the government negotiated lower prices for. These include Stelara (ustekinumab), Prolia (denosumab), and Xolair (omalizumab). Insurers can’t exclude them. That’s huge. But here’s the twist: they’ll still push biosimilars hard. By 2026, 65% of plans are expected to require generic substitution wherever possible. The FDA is also accelerating approval of biosimilars. In 2024 alone, 17 new ones were approved-up 34% from the year before. Experts predict biosimilars will make up 45% of targeted therapy prescriptions by 2027, up from 28% in 2024. That means more switches, more savings, and more pressure on patients to adapt.
Who Gets Left Behind?
The system works well for people who are informed, proactive, and have strong doctor support. But not everyone can navigate this. Elderly patients without tech access may miss their SOC notices. People with multiple chronic conditions may struggle to manage multiple switches. Those without reliable transportation or caregivers can’t easily switch pharmacies or get exceptions processed. Dr. Karen Ignagni, former CEO of America’s Health Insurance Plans, warned: "Over-aggressive generic substitution could disrupt chronic disease management for vulnerable populations if not implemented with clinical oversight." She’s right. Cost savings shouldn’t come at the cost of health.What’s Next? Stay Ahead of the Changes
Formulary updates aren’t going away. They’re becoming more frequent, more complex, and more tied to federal policy. Your best defense is awareness. - Set a calendar reminder for October 1 each year. That’s when your plan’s new formulary drops. - Keep a printed list of all your medications, including dosages and why you take them. Bring it to every appointment. - Talk to your doctor about your concerns. Ask: "If my drug gets switched, what’s the backup plan?" - If you’re on a specialty drug, consider joining a patient advocacy group. They track formulary changes and help with appeals. The system is designed to save money. But it shouldn’t be designed to make you sick. You have rights. You have options. And you’re not alone.What should I do if my insurance switches my medication without telling me?
If your medication was changed without notice, contact your pharmacy and your insurer immediately. You’re entitled to a 30-day transitional supply of your old drug. Ask for a copy of your plan’s formulary update notice. If it wasn’t sent 60 days in advance (as required by CMS), file a complaint with Medicare. Then, work with your doctor to submit an exception request. Don’t stop taking your medication unless instructed by a healthcare provider.
Are biosimilars as safe as brand-name drugs?
Yes, for most people. Biosimilars are rigorously tested by the FDA to be "highly similar" to the original biologic, with no clinically meaningful differences in safety or effectiveness. However, because they’re made from living cells, not chemicals, a small percentage of patients may respond differently. If you’ve been stable on a brand-name drug like Humira, talk to your doctor before switching. Monitor for changes in symptoms after the switch. Most people experience no issues, but it’s not a one-size-fits-all solution.
Can I be switched to a generic if I’m allergic to something in it?
Yes, but you can fight it. Insurers can’t force you to take a drug that contains an ingredient you’re allergic to. Your doctor must document the allergy and submit an exception request. The plan must approve it. If they deny it, you can appeal to Medicare. Never assume your allergy will be ignored. Be proactive. Keep your allergy list updated with every provider and pharmacist.
Why do some drugs get excluded entirely from formularies?
Drugs are often excluded because they’re expensive and have cheaper, equally effective alternatives. Insurers use data to decide which drugs are "redundant" or "low-value." For example, if three similar drugs exist, and two are generics, the third brand-name drug might be cut. The goal is to reduce spending without reducing health outcomes. But sometimes, the excluded drug is the only one that works for a specific patient. That’s why exception requests are critical.
Will my drug costs really be capped at $2,000 in 2025?
Yes, for Medicare Part D enrollees. Starting January 1, 2025, you won’t pay more than $2,000 out-of-pocket for covered drugs in a calendar year, regardless of how expensive your medications are. This includes all copays, coinsurance, and what you pay in the coverage gap. This cap applies only to drugs covered by your plan. If your drug isn’t on the formulary and you don’t get an exception, it doesn’t count. But for most people on chronic meds, this will be a major financial relief.
