In limited circumstances, yes — but Medicare Part D plans face significant restrictions on mid-year formulary changes. Generally, plans cannot remove a drug from formulary mid-year, increase its cost-sharing tier, or impose new restrictions on existing users without specific exceptions and member notice.
Allowed mid-year formulary changes:
1. Generic drug additions (immediate):
- When a generic version of a brand-name drug becomes available, plans can add it to formulary immediately at lower tier
- Brand-name drug may be moved to higher tier or removed simultaneously
- 60-day notice required to affected members
2. FDA safety actions:
- If FDA withdraws a drug for safety reasons, plans can immediately remove it
- If FDA issues new safety warnings, plans can add restrictions (PA, quantity limits)
- Plans must notify affected members and provide alternatives
3. Adding drugs to formulary (always allowed):
- Plans can ADD coverage of new drugs anytime
- No notification timing requirements (it's a benefit improvement)
- Especially relevant for newly-FDA-approved drugs
4. New drugs to market:
- Plans must provide a transition supply (typically 30 days) when a new drug becomes available that requires PA or step therapy
- Then the regular PA/step process applies
Restrictions on mid-year changes:
Plans CANNOT (mid-year):
- Remove non-generic-replaced drugs from formulary
- Move non-generic-replaced drugs to higher tiers
- Add new prior authorization requirements for existing users
- Add new step therapy requirements for existing users
- Add new quantity limits for existing users (with limited exceptions)
Plans CAN (with proper notice):
- Make changes for the upcoming plan year (effective January 1)
- Make changes that improve coverage
- Make changes for safety reasons (with FDA support)
Annual formulary changes (the big one):
The largest formulary changes happen between plan years. Carriers can:
- Drop drugs from formulary entirely
- Move drugs to higher tiers (e.g., Tier 3 → Tier 4)
- Add prior authorization, step therapy, quantity limits
- Change preferred-pharmacy arrangements
Required member notification:
For any annual formulary change affecting your medications, your plan must:
- Send Annual Notice of Change (ANOC) by September 30 of the prior year
- Send Evidence of Coverage (EOC) listing all changes
- Highlight changes affecting drugs you've had filled at the plan in the prior 12 months
- Provide 60-day notice of mid-year changes when permitted
Reading your ANOC:
The ANOC arrives in late September each year. Check specifically:
1. Are any of your medications being removed?
2. Are tier placements changing?
3. Is prior authorization being added?
4. Are quantity limits being added?
5. Is the preferred-pharmacy network changing?
6. Is your monthly premium changing?
7. Is your deductible changing?
Most members don't read the ANOC carefully. The result: surprise formulary changes that catch them at the pharmacy in January.
What to do if your drug is removed or moved up tiers:
Option 1 — Switch plans during AEP (Oct 15 - Dec 7):
The ANOC arrives in time. If your drug is being penalized on your current plan, AEP is your window to switch to a plan with better coverage of that drug.
Option 2 — Request a tiering exception:
- Ask your plan to cover a higher-tier drug at a lower-tier copay
- Your doctor submits clinical justification (other tier drugs ineffective or contraindicated)
- Plan must respond within 72 hours (24 hours if urgent)
- Approval rates vary widely; specialty drugs with high utilization may be approved more readily
Option 3 — Request a formulary exception:
- Ask your plan to cover a non-formulary drug
- Stricter criteria than tiering exception
- Doctor must document why formulary alternatives are inappropriate
- If approved, drug is typically covered at the highest non-specialty tier
Option 4 — Switch to a clinically equivalent alternative:
- Most drug categories have multiple options
- Your doctor can prescribe an alternative that's better-covered on your plan
- Common substitutions: ARB to ACE inhibitor for blood pressure, brand to generic, one statin to another
Special enrollment periods triggered by formulary changes:
In rare cases, a plan's formulary changes are significant enough to trigger an SEP allowing you to switch outside of AEP:
- Plan exits the market entirely
- Plan loses contract with CMS
- Plan's Star Rating drops to 1 star
The 5-star plan SEP:
If there's a 5-star Part D or MA-PD plan in your area, you can switch to it once between December 8 and November 30 the following year — outside AEP. Use this if your current plan's formulary doesn't fit your needs.
Continuous SEP for dual-eligibles and Extra Help recipients:
If you have full Extra Help / Low Income Subsidy or are dual-eligible, you can switch Part D plans:
- Once per quarter (Jan-Mar, Apr-Jun, Jul-Sep)
- Plus standard AEP
- Total: 4 plan-switching opportunities per year
This flexibility is critical for low-income beneficiaries facing mid-year formulary changes.
Watch for in 2026:
The Inflation Reduction Act lets Medicare negotiate prices for high-spend drugs. The first 10 negotiated drugs take effect 2026:
- Eliquis, Jardiance, Xarelto, Januvia, Farxiga, Entresto, Enbrel, Imbruvica, Stelara, Fiasp/NovoLog
Negotiated prices may shift formulary placement and prior authorization requirements as carriers adjust to new economics. Watch ANOCs especially carefully for these drugs.
What to do next: Call (866) 534-1886. We monitor formulary changes affecting Medicare members and recommend plan switches at AEP if your current plan's coverage of your medications is deteriorating. Free, with our Drug Pricing Tool integrated. (866) 534-1886.