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What tier is my medication? Understanding the formulary, prior authorization [PA], and step therapy [ST]

What do the drug tiers mean, and what are [PA] and [ST] on the formulary? Here's how to read your covered drug list and figure out your medication copay.

Checking whether your medication is covered? The formulary (your plan's covered drug list) uses a few codes worth knowing. Here's how to read it.

What are drug tiers?

Every covered medication is assigned a tier, and your copay depends on the tier. Lower tiers are lower cost:

  • Tier 1: most generics — the lowest copay on every plan

  • Tiers 2–3: higher-tier generics and preferred brand medications

  • Tier 4: non-preferred brands and specialty medications

Your plan overview lists your exact copay for each tier. Which tiers are covered varies by plan — for example, some plans cover all four tiers with copays, while others cover Tier 1 with a copay and offer discounts on the rest. Check your plan overview to see how yours works.

Reading the formulary

  • lower-case names are generic drugs (e.g., ibuprofen)

  • CAPITALIZED names are brand-name drugs (e.g., ABILIFY MAINTENA)

  • [PA] — Prior Authorization: your doctor needs approval from the plan before this medication is covered. Your prescriber's office typically handles this — it's routine, but plan a few extra days before filling

  • [ST] — Step Therapy: the plan asks you to try a preferred (usually lower-cost) alternative first. If that doesn't work for you, your doctor can request the original medication

Two good things to know: FDA-approved generics contain the same active ingredients as their brand-name equivalents and meet the same strict standards — so a generic is usually the easiest way to save. And brand-name drugs can move tiers during the year if a generic becomes available, so it's worth rechecking the formulary at renewal.

How to check your medication

  1. Open the Rx Formulary linked from your plan overview (look for the "Rx Formulary" link)

  2. Find your medication and note its tier and any [PA] or [ST] flags

  3. Match the tier against the prescription copays on your plan overview

The formulary isn't a complete list, and inclusion doesn't guarantee coverage — for a definitive answer on a specific medication and your plan, call PureRx or reach out to us.

Need help with a specific medication?

  • Call PureRx: 1-888-899-5122

  • Email: [email protected]

  • Call: (866) 486-8242

  • Hours: Mon–Fri, 8am–9pm EST

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