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NADAC Weekly Drug Prices

Description

The National Average Drug Acquisition Cost (NADAC) is the price US retail pharmacies actually pay for each drug, surveyed by CMS and published every week as a file of about 30,000 National Drug Codes (NDCs). It is the closest public series to a wholesale generic drug price index in the United States.

This product is the weekly series as a panel: one row per NDC per week, with the prior week's price and week-over-week change, the price 52 weeks earlier and year-over-year change, a flag for whether the price was repriced that week, the FDA labeler of record, and a stock ticker where the labeler is a listed company. A second table is a weekly generic deflation index: median and mean week-over-week and year-over-year change across all generic NDCs, the share of NDCs falling, rising and unchanged, the number repriced, and a chained index level.

How the weekly file behaves, and why it matters for reading the data. Each weekly file is a full snapshot. week_date is the file date. effective_date is when the current price took effect and only moves when CMS reprices. CMS reprices the whole file roughly monthly (about 27,000 NDCs move on a reprice week, dozens otherwise), so the weekly median week-over-week change is zero in about three weeks out of four. Read yoy_change_pct, or share_falling and n_repriced on reprice weeks, or a four-week roll of wow_change_pct.

  • Source: CMS NADAC weekly files via the yearly datasets on data.medicaid.gov; FDA National Drug Code Directory (current products and the excluded-products file) for labeler names; Healthparse curated labeler → ticker map (data/reference/ndc-labeler-tickers.json, 83 companies, 60 listed).
  • Refresh cadence: weekly, the Monday after CMS posts (CMS posts each Wednesday's file within about a week).
  • Row count: 2,666,667 NDC-weeks across 88 weeks, 2025-01-01 to 2026-09-02 (2026-09-08 export); about 30,000 NDCs per week. Index: 88 weekly rows. History before 2025 is loaded on the next off-peak run (the 2024 file is staged), which also fills year-over-year for 2025 weeks.
  • Coverage: every NDC has a labeler name; 61% of NDCs carry a ticker. The rest are private manufacturers (Camber/Hetero, Apotex, Rising, Chartwell, Padagis, Lannett, Macleods and similar), which carry company but a null ticker.
  • Vintage: derived at export from the latest week loaded.

Table: nadac_weekly_prices

Snowflake: HEALTHPARSE_DATA.NADAC_DRUG_PRICES.NADAC_WEEKLY_PRICES

Column Type Description Notes
ndc VARCHAR 11-digit National Drug Code (5-4-2, zero-padded). Key with week_date.
week_date DATE Date of the weekly NADAC file (its "as of" date). The time axis. Wednesdays.
effective_date DATE When the current price took effect. Moves only on a reprice.
ndc_description VARCHAR Drug description as published: name, strength, form. e.g. ATORVASTATIN 40 MG TABLET.
ingredient VARCHAR Best-effort molecule or brand: the description up to the first token containing a digit. Heuristic; misses names like VITAMIN D3; brands yield the brand name.
classification VARCHAR G generic, B brand, B-ANDA brand marketed under a generic approval, B-BIO biologic. Filter to G for generic deflation.
otc_indicator VARCHAR Y over the counter, N prescription. —
pricing_unit VARCHAR EA, ML or GM. Prices are per unit.
pharmacy_type VARCHAR C/I chain and independent. —
labeler_code VARCHAR First NDC segment, 5 digits. Joins to the FDA directory.
labeler_name VARCHAR Labeler of record from the FDA NDC Directory. 100% populated.
ticker / exchange / company VARCHAR Listed parent of the labeler where one exists, from the curated map. Labeler of record, so a distributor private label (e.g. McKesson's) maps to the distributor.
nadac_per_unit NUMERIC The price this week, dollars per unit. —
prior_week_date / prior_week_nadac_per_unit DATE / NUMERIC The previous weekly file and its price for this NDC. Prior week must be within 14 days.
wow_change_pct NUMERIC Week-over-week change, percent. Zero in most non-reprice weeks.
price_changed_this_week BOOLEAN True when the price differs from the prior week. Reprice flag.
week_52w_ago / nadac_52w_ago DATE / NUMERIC The file 364 days earlier and its price. Falls back to 357 or 371 days.
yoy_change_pct NUMERIC Year-over-year change, percent. Null for 2025 weeks until 2024 loads.
corresponding_generic_drug_nadac_per_unit NUMERIC For a brand, the NADAC of its generic equivalent. Brand-to-generic spread.
_dataset / _vintage / _exported_at VARCHAR See README. —

Table: nadac_generic_index_weekly

Snowflake: HEALTHPARSE_DATA.NADAC_DRUG_PRICES.NADAC_GENERIC_INDEX_WEEKLY

One row per week across all generic (G) NDCs.

Column Type Description
week_date DATE Weekly file date.
n_ndcs / n_ndcs_with_prior / n_ndcs_with_yoy INTEGER Generic NDCs in the file, and how many have a prior-week or 52-week comparison.
median_wow_change_pct / mean_wow_change_pct NUMERIC Equal-weighted week-over-week change across generic NDCs.
share_falling / share_rising / share_unchanged NUMERIC Share of generic NDCs whose price fell, rose or held versus the prior week.
n_repriced INTEGER Generic NDCs whose price changed this week. About 27,000 on a reprice week, dozens otherwise.
median_yoy_change_pct / mean_yoy_change_pct NUMERIC Year-over-year change across generic NDCs. The cleanest deflation read.
index_level_median_chain NUMERIC Chained index of the median week-over-week change, base 100 at 2025-01-01.

Example queries (Snowflake)

-- 1. Generic deflation by listed manufacturer: median YoY price change of
--    each ticker's generic NDCs in the latest week.
SELECT "ticker", "company", count(*) AS ndcs,
       median("yoy_change_pct") AS median_yoy_pct
FROM HEALTHPARSE_DATA.NADAC_DRUG_PRICES.NADAC_WEEKLY_PRICES
WHERE "week_date" = (SELECT max("week_date") FROM HEALTHPARSE_DATA.NADAC_DRUG_PRICES.NADAC_WEEKLY_PRICES)
  AND "classification" = 'G' AND "ticker" IS NOT NULL AND "yoy_change_pct" IS NOT NULL
GROUP BY 1, 2 HAVING count(*) >= 50 ORDER BY median_yoy_pct;

-- 2. One molecule's weekly price across labelers.
SELECT "week_date", "labeler_name", "ticker", "nadac_per_unit", "price_changed_this_week"
FROM HEALTHPARSE_DATA.NADAC_DRUG_PRICES.NADAC_WEEKLY_PRICES
WHERE "ndc_description" = 'ATORVASTATIN 40 MG TABLET'
ORDER BY "week_date" DESC, "labeler_name";

-- 3. The deflation index: reprice weeks only.
SELECT "week_date", "n_repriced", "share_falling", "median_yoy_change_pct", "index_level_median_chain"
FROM HEALTHPARSE_DATA.NADAC_DRUG_PRICES.NADAC_GENERIC_INDEX_WEEKLY
WHERE "n_repriced" > 1000 ORDER BY "week_date";

Known limits

  • NADAC is a retail pharmacy acquisition price, not a manufacturer net price. It excludes rebates and specialty and mail channels, and it is a survey average, not a transaction record.
  • Repricing is roughly monthly. Weekly changes are zero for most NDCs in most weeks; use year-over-year or reprice-week measures.
  • Ticker is by labeler of record. A drug sold under a distributor's or repackager's label maps to that company, not to the manufacturer.
  • The ingredient column is a heuristic on the description text, not a reference to an ingredient database.
  • History starts 2025-01-01 in this export; 2024 loads next, which also fills year-over-year for 2025 weeks.