TwinFyRxTwinFyRx Labs · Medicare Drug Atlas
Every drug Medicare paid for, in one picture
1.36B Part D prescriptions from 2024, arranged by the WHO's ATC classification. Click a circle to zoom from anatomical group down to the ingredient. Then size the circles by spend instead of prescriptions and watch the map redraw itself: the drugs Medicare fills most are not the drugs it pays the most for.
Click a circle to zoom in · click the background or a breadcrumb to zoom out
All Part D drugs
The 1,058 ingredients with 1,000+ claims
What to look for
72.5M fills, $752M. Size by spend and it nearly disappears.
$13.8B on 0.8% of fills. The top 10 ingredients take 33% of all spend.
34% of fills but 8% of spend. By spend, alimentary tract and metabolism leads with 31%.
How it's built
CMS publishes Part D prescribing as free-text brand and generic names. TwinFyRx resolves every name onto RxNorm ingredients, so a fill joins pricing, formulary and indication data on the same keys.
Prescriber Intelligence Lab →Each ingredient sits under the primary ATC code of its products: the code for its route and main use. Combination products keep the WHO's dedicated combination code, so they're one circle here.
What is ATC classification? →Class and ingredient totals, prescriber mix and per-prescriber volume are in the prescriber endpoints, keyed by ATC code and ingredient RxCUI.
API reference →Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024. Drug names mapped to RxNorm ingredients and classified with the WHO ATC/DDD Index by TwinFyRx. Shows the 1,058 ingredients with at least 1,000 claims (over 99.9% of all claims); 1.2% of claims have no ATC code yet, mostly newer vaccines, and sit under “Unclassified”. Spend is CMS's gross drug cost, before rebates. CMS suppresses prescriber × drug rows under 11 claims, so totals are lower bounds.