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Part D formularies change, and tiers drive your cost
Part D plans use formularies (covered-drug lists), tiers, and rules like prior authorization, quantity limits, and step therapy. Formularies and costs can change from year to year—even if your health stays the same.
Why it Matters
Your medication costs can jump unexpectedly if a drug changes tier, requires approval, or is removed from the formulary.
Action Steps
Check that each medication is on your plan’s formulary.
Ask about lower-cost alternatives if a drug is high tier.
Review drug coverage during the annual enrollment period.
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