Yes, most employer-sponsored and individual health insurance plans cover prescription drugs, but the specifics depend on your pharmacy benefits. Those benefits determine what's covered, how much you pay, and the rules you follow. In most plans, they're managed by a Pharmacy Benefits Manager (PBM), a third-party company that negotiates drug prices with manufacturers and pharmacies, builds the formulary, and handles cost-sharing. Understanding this system is important for managing both your health and your budget.
Understanding Prescription Drug Tiers (How the Formulary Works)
To manage costs and encourage the use of clinically effective and cost-efficient medications, PBMs categorize drugs into a tiered system called a formulary. Each tier has a different out-of-pocket cost. The structure is consistent across most plans, though specific drugs vary and some plans use only three or four tiers. KFF's 2025 Employer Health Benefits Survey found 84% of covered workers are in plans with three or more drug tiers.
- Tier 1: Preferred Generic Drugs - The cheapest option. Common generic meds. The copay is usually small, often as little as $0.
- Tier 2: Non-Preferred Generic Drugs - Generic drugs that may have a preferred alternative or are newer generics. Copay is a bit higher than Tier 1.
- Tier 3: Preferred Brand-Name Drugs - Brand-name drugs the PBM got a deal on. They carry a higher copay or coinsurance.
- Tier 4: Non-Preferred Brand-Name Drugs - Brand-name drugs without preferred status or with a generic equivalent. Often the most expensive tier before specialty drugs, usually paid as coinsurance.
- Tier 5: Specialty Drugs - High-cost medications for complex conditions like cancer or multiple sclerosis. Almost always require coinsurance and may have extra requirements like prior authorization or specialty pharmacy fulfillment.
Copays are not universal. In many plans, especially high-deductible health plans paired with a health savings account, prescriptions are subject to the deductible first. You pay the full negotiated price for non-preventive drugs until you meet the deductible, and only then do copays or coinsurance kick in. Check your plan's Summary of Benefits to see which model applies to you, and note the out-of-pocket maximum, which caps your total annual spending on covered care, including drugs.
Biosimilars Are Changing the Specialty Tier
Biosimilars are near-identical, FDA-approved versions of biologic drugs, and they usually cost less than the original. Their arrival is rewriting the higher tiers. Humira, a widely prescribed biologic for rheumatoid arthritis and other conditions, is the clearest example. Since 2023, a wave of Humira biosimilars has reached the U.S. market, and by 2025 the major PBMs had moved brand Humira off their preferred positions: Express Scripts excluded it from its 2026 national formulary, while Optum Rx kept it on tier 3 and placed the biosimilar Amjevita on tier 2. The HHS Office of Inspector General found that most Medicare Part D plans covered Humira biosimilars in 2025, though almost none used preferential tier placement to steer patients toward them. If you take an expensive biologic, ask whether a biosimilar sits on a lower tier. For HR leaders, pushing a formulary toward biosimilars is one of the fastest levers for cutting specialty drug spend.
Key Mechanisms That Affect Access and Cost
Beyond tiers, standard PBM mechanisms control utilization and cost. Prior Authorization (PA) requires your doctor to prove medical necessity before the plan covers a specific, often expensive, drug. Step Therapy mandates you try a lower-cost drug first before a higher-tier alternative is covered. Quantity Limits restrict how much you can get per fill or over time. Your plan's network dictates which pharmacies you can use at the covered rate; using an out-of-network pharmacy often means much higher costs or no coverage at all.
The Emerging Critique and a New Model
The traditional PBM model has faced growing criticism for opaque "spread pricing," where the PBM charges the plan more than it pays the pharmacy and pockets the difference, and for rebate structures that can encourage high list prices. That leaves employers and employees confused about the real cost of medications.
Innovative models are emerging to address these flaws. WellthCare is the first Health-to-Wealth Benefit System, combining $0-co-pay care with Store rewards and automatic retirement contributions. Its WellthCare Pharmacy™ replaces traditional PBMs with transparent, pass-through pricing, typically lowering drug costs by 20–40% with no spread games. The pharmacy integrates directly into the Health-to-Wealth system and ties prescription benefits to personalized plans of care, using the savings to fund employee rewards and automatic retirement contributions. Better health and smarter spending build wealth for the employee while lowering costs for the employer.
What You Can Do: Actionable Steps
For Employees: Before you fill that next prescription, check your plan's formulary; it's usually on your insurer's portal or HR site. Ask your doctor if a Tier 1 or 2 alternative works for you. Staring at a high-cost drug? Talk to your doctor about prior authorization or step therapy rules. If you take maintenance meds, a preferred mail-order pharmacy can get you a 90-day supply for less.
For HR & Benefits Leaders: Dig into your PBM contract and demand transparency on pricing and rebate pass-through. Look at newer pharmacy models that focus on net cost and health outcomes over rebate revenue. Educate your workforce on how their pharmacy benefits work; understanding tiers and prior authorization can prevent surprise bills and improve medication adherence, leading to better health and lower overall plan costs.
Prescription drug coverage is a standard but complex piece of healthcare benefits. Get to know your tiers and the rules; that's the best way to control costs. Newer models go beyond simple coverage by integrating pharmacy benefits into a system that builds employee health and financial wellness.