Drug Pricing Transparency: What Medicare Pays Per Day

Americans pay more for prescription drugs than any other country. This post uses CMS Medicare Part D spending data – covering ~3,600 drugs from 2019 to 2023 – to visualize where $276 billion in annual drug spending goes, which drugs cost the most per day, and how prices have changed over five years.

Medicare Part D spent $276 billion on prescription drugs in 2023. The top 10 drugs alone — led by Eliquis at $18.3 billion — accounted for 26% of all spending. The most expensive drug by daily cost runs over $850/day. GLP-1 drugs like Ozempic and Trulicity now represent a $34+ billion category and are growing fast. Price growth varies wildly: some drugs have compounded at 10%+ annually while others have dropped.

Americans pay more for prescription drugs than any other country. Part of the reason is opacity: drug prices are negotiated in private between manufacturers, pharmacy benefit managers, and insurers. But one major payer — Medicare Part D — publishes its spending data annually. The result is the most comprehensive public window into what the US actually pays for drugs.

The CMS Medicare Part D Spending by Drug dataset covers every drug with sufficient Medicare claims (roughly 3,600 brand and generic drugs), with annual spending, claim counts, beneficiary counts, and average costs per fill. It covers 2019–2023, providing a five-year view that captures the pandemic disruption, the GLP-1 explosion, and ongoing price escalation in specialty drugs.

Total 2023 spending: $276 billion across all Part D drugs. For context, that's more than the entire federal discretionary budget for education, transportation, and energy combined.

Each block represents one drug, sized by total 2023 Medicare Part D spending. Color shows the 5-year compound annual growth rate in price per dosage unit — red means fast price growth, blue means prices have declined.

A few things stand out in the landscape:

• Eliquis dominates. The blood thinner apixaban (Eliquis) is Medicare's single largest drug expense at $18.3 billion — nearly twice the second-place drug. Its patent has been challenged but held; a wave of generic competition is expected in coming years.
• Blood thinners and diabetes drugs are the biggest categories. Eliquis, Xarelto, Jardiance, Farxiga, and the GLP-1 drugs collectively account for a disproportionate share of total Part D spending.
• Many large drugs have steady price growth. The orange-to-red tint on drugs like Humira, Eliquis, and Trulicity reflects consistent price increases compounding at 5–10% annually over five years.
• Some drugs have seen prices fall. Blue-tinted drugs include some generics and drugs that faced biosimilar or generic competition during this period.

"Cost per day" cuts through confusing per-unit pricing to give an intuitive sense of what a drug actually costs to take. This shows the 40 highest daily-cost drugs in Medicare Part D, restricted to drugs with at least 50,000 claims.

The most expensive drug by daily cost is Vyndamax (tafamidis), a treatment for transthyretin amyloid cardiomyopathy — a rare heart condition — at roughly $860/day. Stelara (ustekinumab), a biologic for psoriasis and Crohn's disease, runs about $850/day. Both are biologics: large-molecule drugs that are expensive to manufacture and face limited competition.

For context:

• The most expensive drugs on this list are almost exclusively biologics or specialty oncology drugs
• Many GLP-1 drugs (Ozempic, Trulicity, Mounjaro) appear in the mid-tier — expensive but not at the extreme top end
• Blood thinners (Eliquis, Xarelto) dominate total spending due to massive volume despite moderate daily cost

How has spending evolved from 2019 to 2023 for the top drugs?

The most dramatic story is Ozempic (semaglutide). Barely a rounding error in 2019 Part D spending, it reached $9.2 billion by 2023 — entirely driven by volume, as GLP-1 prescriptions exploded first for diabetes management and then for weight loss. Jardiance and Farxiga (SGLT-2 inhibitors) show similar trajectories.

Eliquis has grown steadily throughout, driven by both price increases and aging-population volume growth in atrial fibrillation. Revlimid (lenalidomide, for multiple myeloma) peaked and then declined as generic competition entered after 2022.

Humira (adalimumab) shows an unusual pattern: total spending held roughly flat even as biosimilar competition should have reduced it, because the branded version maintained pricing while biosimilar uptake was slower than expected.

Total drug spending is driven by two factors: price per unit and volume of prescriptions. This scatter shows how both changed from 2022 to 2023. Drugs in the upper-right quadrant are becoming more expensive to treat and being used more — a double driver of spending growth.

The upper-right quadrant — price up and volume up — is where policymakers focus. GLP-1 drugs (Ozempic, Mounjaro) appear here with explosive volume growth, though their price per unit has been more controlled. Blood thinners sit near the center: modest price increases, stable or slowly growing volume.

Drugs in the upper-left (volume up, price down) often reflect generics entering the market or manufacturer rebates increasing. The lower-right (price up, volume down) may indicate drugs losing market share as alternatives emerge, but still raising prices on their remaining users.

The Inflation Reduction Act (IRA) of 2022 gave Medicare the authority to negotiate drug prices directly for the first time in its history. The first round of negotiations covered 10 drugs, including Eliquis and Xarelto, with negotiated prices taking effect in 2026. The second round expanded the list.

The data here shows why this matters: these drugs represent tens of billions in annual Medicare spending, and their prices have compounded upward for years in a market where Medicare previously had no negotiating power. The projected savings from negotiation are modest relative to total spending — but the precedent is significant.

For GLP-1 drugs, the policy debate is different. These drugs have demonstrated clinical benefit not just for diabetes but for cardiovascular outcomes and obesity-related conditions. The question isn't whether prices are too high in isolation, but how Medicare balances access (these drugs could benefit tens of millions of beneficiaries) against budget impact at scale.

All data from the CMS Medicare Part D Spending by Drug dataset (2019–2023).

• Coverage: Drugs with sufficient Medicare Part D claims to meet CMS's minimum reporting threshold (10+ prescribers, 11+ beneficiaries per year). Approximately 3,600 drugs included.
• "Overall" rows: The dataset includes one row per drug per manufacturer, plus an "Overall" aggregate row. All analysis here uses the "Overall" rows.
• Cost per day: Calculated as average spending per claim divided by 30 (assumes a 30-day supply per claim, a standard Part D fill). This is an approximation; some drugs have different supply durations.
• Price change: Chg_Avg_Spnd_Per_Dsg_Unt_22_23 is the year-over-year change in weighted average spending per dosage unit (2022→2023). The 5-year CAGR covers 2019→2023.
• Volume change: Change in total claims count from 2022 to 2023.
• Minimum thresholds: The cost-per-day chart requires ≥50,000 annual claims; the scatter requires ≥100,000 to reduce noise from low-volume drugs.