A pharmaceutical formulary is a dynamic, evidence-based list of prescription drugs that a health plan, pharmacy benefit manager (PBM), or insurer covers. Think of it as the plan's curated menu of medications. Not every drug on the market makes the cut. The formulary is designed to balance clinical effectiveness, safety, and cost, steering both the employer (who pays the bills) and the employee (who uses the medication) toward high-value treatment options.
In the context of employer-sponsored benefits, the formulary is the single most powerful tool an employer or PBM has to manage prescription drug costs. It directly determines which drugs are covered, at what tier, and under what conditions. For employees, the formulary dictates their out-of-pocket expenses, from copays to coinsurance to whether they need prior authorization. Understanding how a formulary works is key for anyone designing, purchasing, or using healthcare benefits.
How a Formulary Is Built
Formularies aren't static. They're built and updated regularly by a Pharmacy and Therapeutics (P&T) committee composed of independent physicians, pharmacists, and other clinical experts. This committee evaluates drugs based on:
- Clinical efficacy: Does the drug work as intended for the approved condition?
- Safety profile: What are the side effects, drug interactions, and risks?
- Cost-effectiveness: Is there a therapeutically equivalent generic or brand alternative at a lower cost?
Based on this review, drugs are assigned to tiers. The most common tiered structure is a 3-4 tier system:
- Tier 1: Generic drugs - lowest copay, most cost-effective
- Tier 2: Preferred brand-name drugs - moderate copay
- Tier 3: Non-preferred brand-name drugs - higher copay or coinsurance
- Tier 4 (often): Specialty drugs - highest cost, often requiring prior authorization or step therapy
How the Formulary Directly Affects Prescription Drug Coverage
The formulary is the filter through which all prescription claims pass.
1. Out-of-Pocket Costs for Employees
If a drug is on formulary and in a lower tier, the employee pays a fixed, predictable copay. If the drug is non-formulary or in a higher tier, the employee may face coinsurance (a percentage of the drug cost), a much higher deductible, or no coverage at all. This can be the difference between a $10 copay and a $500 monthly outlay.
2. Prior Authorization and Step Therapy
Many formularies include utilization management tools. Prior authorization requires the prescriber to prove medical necessity before the plan will cover the drug. Step therapy requires the patient to try a lower-cost, equally effective alternative first before the plan will cover a more expensive drug. These tools are designed to prevent waste and align medication use with evidence. A 2019 JAMA analysis estimated that roughly a quarter of U.S. healthcare spending is waste, driven by pricing failures, overtreatment, and administrative complexity. WellthCare™, the first Health-to-Wealth Benefit System, goes further by aligning the entire incentive structure, rewarding preventive health actions with Store reward dollars and automatic retirement contributions, and providing $0-co-pay care that reduces waste and claims.
3. Coverage for New or Specialty Drugs
Specialty drugs, including biologics, GLP-1 agonists for weight management, and gene therapies, are almost always placed on the highest tier. This means the employee may face high coinsurance or a separate deductible before coverage kicks in. The formulary is also updated regularly: new drugs are reviewed and added when they offer demonstrable clinical advantage over existing options. This constant updating means employees may find a drug covered one year and placed on a higher tier the next, a key point for benefits communication during open enrollment.
4. Employer Cost & Premium Impact
Because prescription drug spending is a leading driver of healthcare cost inflation, the formulary directly affects employer premiums. A well-managed formulary that emphasizes generics and step therapy can reduce drug spend. A 2021 Johns Hopkins study of two large self-insured employers found that swapping costlier drugs for clinically equivalent, lower-priced options cut annual prescription spending by 9-15%. Conversely, an overly permissive formulary (one that includes high-cost brands without clinical justification) can spike claims costs. Smart benefits leaders, especially those moving toward self-funded plans, use the formulary as an important tool in plan design, often pairing it with the WellthCare Readiness Index™ to benchmark savings opportunities.
How Rebates Shape the Formulary
Clinical review is only part of how a formulary comes together. Manufacturer rebates also shape the list. A drugmaker pays the PBM or plan a rebate in exchange for preferred placement, and a high-list-price drug can support a bigger rebate than a lower-priced rival. That can push a costlier brand into a better tier while a cheaper generic or biosimilar stays off the formulary. The FTC's July 2024 interim report found evidence that PBMs and manufacturers sometimes agree to exclude lower-cost generics and biosimilars from formularies in exchange for larger rebates. In September 2024 the FTC sued the three largest PBMs over rebate practices it said inflated insulin list prices and shifted costs to patients. When the PBM keeps the rebate instead of passing it through, the employer's formulary is not built around the lowest net cost. Employers can ask whether rebates pass through and whether placement follows net cost rather than list price.
The WellthCare Ecosystem Perspective
At WellthCare, we see the formulary as part of a larger, broken system. Traditional PBMs derive profit from spread pricing, charging employers a higher rate for a drug than what the PBM pays the pharmacy and pocketing the difference. This opaque structure is a source of massive waste. WellthCare Pharmacy™ replaces this with transparent, aligned pricing that cuts out the PBM middleman, reduces drug costs by 20-40%, and ties medication use to the employee's plan of care. By integrating the formulary into a Health-to-Wealth system, where preventive actions earn reward dollars and automatic retirement contributions, we shift the focus from managing sickness through high-cost medication to preventing it in the first place.
What Employees Need to Know
For the employee, the formulary isn't optional; it's central to their healthcare experience. Here are three actionable takeaways:
- Check the formulary before filling a prescription. A simple online lookup can save hundreds per month by identifying a covered generic or preferred brand.
- Talk to your doctor about step therapy options. If a non-preferred drug is prescribed, ask if a therapeutically equivalent alternative on a lower tier exists.
- Use your plan's mail-order or pharmacy network. Most formularies offer significant discounts for using preferred pharmacies or 90-day supplies.
If the drug you need is non-formulary, plans generally allow your prescriber to request a formulary exception, and you can appeal a coverage denial. These reviews exist because no formulary fits every patient.
The formulary isn't a barrier to care; it's a tool for smarter, more affordable coverage. When aligned with a system that rewards preventive health and builds wealth, it becomes part of a structural redesign of benefits that works for both employees and employers. That's the future: healthcare that pays you back.