Medicare Part D Trends: 2019-2023
Five years of prescribing data reveal dramatic shifts in drug costs, opioid prescribing, and the brand-generic divide.
Data: CMS Medicare Part D, 2023 (most current available) · Updated March 2026
+51%
Cost Growth
$275.65B
2023 Total Cost
-2%
Opioid Prescriber Change
1,380,665
2023 Providers
Drug Cost Trends
Opioid Prescribing Trends
The Cost Explosion
Medicare Part D drug spending grew from $183.05B in 2019 to $275.65B in 2023 — a 51% increase over five years. This growth far outpaces inflation and reflects several converging forces:
- New specialty drugs — GLP-1 drugs (Ozempic, Mounjaro) barely existed in 2019; by 2023 they accounted for $8.5 billion
- Brand-name pricing — Brand drugs cost an average of $880 per claim vs $29 for generics
- Medicare enrollment growth — More beneficiaries entering the system
- Biologic medications — High-cost biologics for cancer, autoimmune diseases, and rare conditions
The Opioid Prescribing Decline
One bright spot: opioid prescribing continues to decline. The percentage of providers prescribing opioids dropped from 36.9% in 2019 to 32.6% in 2023. The number of high-rate opioid prescribers (above 20% of claims) fell from 126,837 to 113,169.
However, this decline in prescribing hasn't translated to a proportional decline in overdose deaths. The crisis has shifted from prescription opioids to illicit fentanyl — a transition our data captures on the supply side but not the demand side.
Brand vs Generic
The brand-generic mix has shifted slightly toward generics over five years. Brand prescriptions went from 15.2% of all claims in 2019 to 13.4% in 2023. But because brand drugs are so much more expensive per claim, they still account for approximately 67% of total costs.
Year-by-Year Data
| Year | Total Cost | Claims |
|---|---|---|
| 2019 | $183.05B | 1,502,024,872 |
| 2020 | $198.51B | 1,496,175,155 |
| 2021 | $215.52B | 1,498,820,252 |
| 2022 | $240.22B | 1,542,626,610 |
| 2023 | $275.65B | 1,615,685,370 |
What to Watch
- Inflation Reduction Act — Medicare can now negotiate prices on select drugs starting 2026. The first 10 drugs were announced in 2023
- GLP-1 coverage expansion — If CMS extends Part D coverage to weight loss (currently excluded), costs could surge by $50B+
- Biosimilar competition — Humira biosimilars arrived in 2023, potentially saving billions
- Part D redesign — The $2,000 out-of-pocket cap takes effect in 2025