A tier 5 drug is a specialty medication that sits on the highest, most expensive level of an insurance plan’s drug list (called a formulary). These drugs treat complex conditions like cancer, multiple sclerosis, rheumatoid arthritis, and immune deficiencies. They typically cost thousands of dollars per month, and you’ll usually pay 25% to 33% of the retail price out of pocket.
How Drug Tiers Work
Most insurance plans organize their covered medications into three to six tiers, with lower tiers costing you less and higher tiers costing more. Tier 1 usually holds the cheapest generic drugs, with a flat copay of $5 to $15. As you move up, you’ll find preferred brand-name drugs, then non-preferred brands, then specialty drugs. Tier 5 sits at or near the top of this structure.
The key thing to understand: a drug’s tier placement isn’t strictly about how well it works. It reflects a combination of cost, whether cheaper alternatives exist, and the plan’s negotiations with drug manufacturers. A highly effective drug can land on tier 5 simply because it’s expensive to produce, as many biologics and injectable therapies are.
What Makes a Drug “Specialty”
Specialty drugs are distinct from ordinary prescriptions in several ways. They often require special handling, like refrigeration or injection by a healthcare provider. Many are biologics, meaning they’re derived from living cells rather than synthesized chemically, which makes them far more costly to manufacture. Some need to be administered through infusion at a clinic rather than taken as a pill at home.
Common categories of tier 5 drugs include:
- Cancer treatments: injectable therapies like Keytruda, Avastin, and Darzalex, plus oral medications like Ibrance, Revlimid, and Xtandi
- Inflammatory and autoimmune conditions: Humira, Remicade, Stelara, and Skyrizi for conditions like Crohn’s disease, ulcerative colitis, and psoriasis
- Immune deficiency treatments: infused immunoglobulin therapies like Gammagard and Privigen
- Multiple sclerosis drugs, hepatitis C treatments, and HIV medications
A tier 5 drug can be generic or brand name. The “specialty” label comes from the drug’s complexity and cost, not whether a generic version exists.
Where You Can Fill a Tier 5 Prescription
Not every pharmacy dispenses specialty drugs. Your regular retail pharmacy may carry some, but many plans require or encourage you to use a designated specialty pharmacy. These pharmacies are equipped to handle the storage, shipping, and clinical support that specialty medications demand.
Most plans limit specialty drug fills to a 30-day supply at a time, whether you get them from a retail pharmacy or through mail order. Some drugs are restricted further to a 15-day supply per fill. This prevents waste, since treatment plans for these conditions can change quickly, and a single month’s supply may cost tens of thousands of dollars.
Prior Authorization and Step Therapy
Tier 5 drugs almost always come with extra hurdles before your plan will cover them. The most common is prior authorization, where your doctor must submit clinical documentation proving the drug is medically necessary for your specific situation. The insurance plan reviews this before approving coverage.
Many plans also require step therapy, meaning you have to try one or more less expensive drugs first and show they didn’t work before the plan will approve the tier 5 option. For example, you might need to try a conventional anti-inflammatory drug before your plan agrees to cover a biologic for rheumatoid arthritis.
Quantity limits are also standard. Plans cap how much of a drug you can receive in a given period, both for cost control and safety. If you’re switching plans or starting a new one, you can usually get a one-time 30-day transition fill of a specialty drug you’ve been taking, even if the new plan normally requires prior authorization for it.
What You’ll Actually Pay
Unlike lower tiers where you pay a flat copay ($10 or $40, for instance), tier 5 drugs typically use coinsurance, meaning you pay a percentage of the drug’s price. That 25% to 33% coinsurance on a drug that costs $10,000 per month means $2,500 to $3,300 out of your pocket for a single fill.
For people on Medicare Part D, a major change took effect in 2025. The Inflation Reduction Act introduced a $2,000 annual cap on out-of-pocket drug spending. Once you hit that threshold, you pay nothing more for covered prescriptions for the rest of the year. This cap will be adjusted for inflation annually. Before this change, Medicare enrollees taking expensive specialty drugs could face unlimited cost exposure, particularly in the coverage gap (formerly known as the “donut hole”) and beyond. The enrollees who previously had the highest out-of-pocket spending are expected to benefit the most from this cap.
For people with employer-sponsored or marketplace insurance, annual out-of-pocket maximums also apply, but they vary by plan and tend to be higher than Medicare’s new cap.
Reducing Your Out-of-Pocket Costs
Several options can help offset what you owe for tier 5 drugs. Many pharmaceutical manufacturers run patient assistance programs that provide medications at reduced cost or even free to people who qualify based on income. These programs exist for most major specialty drugs.
For people with commercial (non-Medicare) insurance, manufacturer copay cards can dramatically reduce your coinsurance at the pharmacy counter. These cards won’t always count toward your plan’s out-of-pocket maximum, though, so read the fine print.
Independent nonprofit foundations also offer grants to help cover copays for specific conditions. Your specialty pharmacy or doctor’s office can often point you toward the right foundation for your diagnosis. Applying early matters, because many of these funds run out partway through the year.
If your plan places a drug on tier 5 and you believe a lower tier is appropriate, you can request a formulary exception through your insurer. Your doctor will need to provide supporting documentation explaining why the specific drug is necessary and why lower-tier alternatives won’t work for you.