The GxRadar generic price index

By October 2026, a fixed basket of 43 common generics cost retail pharmacies about 53 percent less than it did in January 2014. GxRadar's index of that basket, set to 100 at the start, stood at 47.4, according to our analysis of the weekly drug cost files the federal government publishes through CMS's NADAC dataset¹.

It was not a steady decline. The index barely moved in 2014 and 2015, fell by roughly a tenth a year from 2016 through 2018, stalled for three years, then resumed its slide in 2022. Only seven of the 43 drugs cost more in October 2026 than they did in January 2014.

Most public talk about drug prices concerns brand-name list prices. This index tracks something narrower and, for generics, more telling. It follows what pharmacies pay on invoice for old, widely used medicines that many companies make.

How the basket was chosen

GxRadar tracks 47 generic products on its price history page, each defined as one strength and form, such as the atorvastatin 20 mg tablet or the amoxicillin 500 mg capsule. Forty-three of them had a generic NADAC price in the January 2014 NADAC file². Those 43 make up the basket, and we never add or drop a drug.

Four were left out because they had no generic price in January 2014. The generic valsartan 160 mg series in our data begins in September 2014, duloxetine 60 mg in February 2014, rosuvastatin 10 mg in July 2016 and tadalafil 5 mg in December 2018. Adding them later would mix new generic launches, which tend to fall fast, into a measure of established products.

By therapeutic class, the basket leans toward heart and blood pressure drugs, statins, antidepressants, acid reducers and six antibiotics. Every drug counts equally. A pill taken by tens of millions of people carries the same weight as one taken by far fewer.

The arithmetic behind the number

NADAC, the National Average Drug Acquisition Cost, comes from a voluntary monthly survey of retail community pharmacy invoices, which CMS describes in its December 2024 methodology⁴. Each weekly file lists a per-unit price for every national drug code (NDC) in the survey, along with a field showing whether the NDC was treated as brand ("B") or generic ("G") when the rate was set, as the NADAC data definitions⁵ explain.

We pulled every generic-classified row for our 43 descriptions from the yearly files using the data.medicaid.gov⁶ query interface. Under CMS's rules⁴, a single generic rate applies to every generic-classified NDC in a drug grouping, so the rows for a given week almost always carry the same number. We average them for each week, then take the median of the weekly values in each month.

From there, each drug's monthly price is divided by its January 2014 price. A drug at 0.5 has halved; one at 2.0 has doubled. The index is 100 times the geometric mean of those 43 ratios.

We chose a geometric mean because it treats a halving and a doubling as equal and opposite moves. An ordinary average lets a few big percentage gains swamp many declines. In October 2026 the ordinary average of the 43 ratios gave an index of 64.2, against 47.4 for the geometric version. The median drug stood at 0.57, a 43 percent decline.

What the index shows, year by year

Each row in the table below uses that year's average monthly index value. A drug is counted as cheaper or pricier when its own average for the year moved more than 1 percent from the year before; the rest were roughly flat.

Source: GxRadar analysis of CMS NADAC weekly files, November 2013 through October 2026. Generic-classified rows only.

The flat start reflects the tail of the generic price spikes of 2013 to 2015. The index peaked at 106.2 in February 2014, and 11 of the 43 drugs got more expensive in 2015. An HHS analysis from that period, ASPE's January 2016 brief on generic prices⁷, singled out doxycycline as one of two drugs in its analysis whose large price increases came while the drug was in shortage.

Three years of steep decline followed, and they were broad, with at least 34 drugs getting cheaper in each year from 2016 to 2018. Then the index went sideways. In 2020 it rose by 0.8 percent, the only annual increase in the series, and nearly as many drugs rose (19) as fell (21). We have not tried to assign a cause to each year's movement. Drug-level stories are on the individual drug pages.

Prices resumed their slide in 2022 and have kept falling, with 35 drugs cheaper in 2024 and 36 in the first 10 months of 2026. The series low so far came in December 2024, at 45.7, during the survey swings described below.

Which drugs moved the most

Source: GxRadar analysis of CMS NADAC. Monthly medians of weekly generic rates.

Doxycycline alone does not drive the result. Dropping it raises the October 2026 index only to 50.5. The drugs that rose tend to be ones that were already very cheap in 2014, a group covered in the generics that cost pharmacies more than in 2014. Furosemide nearly tripled, but from about one cent a tablet to about three.

Where the index can mislead

It measures acquisition cost. NADAC is built from invoices, and CMS says discounts or rebates not shown on the invoice at the line-item level are not factored in⁴. Only chain and independent retail community pharmacies are surveyed. The figure also leaves out what the pharmacy is paid for dispensing; Medicaid programs add a separate professional fee, about $10.92 per prescription in New Jersey, for example, according to CMS's state reimbursement table for the quarter ending September 2026¹⁰. None of this is a patient price, which our piece on what pharmacies pay for a month of common generics takes up in more detail.

A fixed basket ages. Every drug in it was already generic in 2014. Price drops are usually steepest in the first few years after generic entry. FDA economists found in a December 2019 study⁸ that with six or more generic makers, prices ran more than 95 percent below the pre-generic brand price, and an ASPE brief from January 2025⁹ found declines of 70 to 80 percent in markets with 10 or more competitors three years after entry. Our basket misses those early declines by design.

One strength per drug stands in for the whole molecule, and the weights ignore how often each drug is used.

The 2024 data are noisy. From 2014 through 2023 the index moved an average of 1.4 percent a month. In 2024 the average was 6.2 percent, and the moves were synchronized. In November 2024 all 43 drugs fell at once and the index dropped 13.3 percent. CMS's methodology⁴ attributes the generic rate volatility to fluctuations in how many pharmacies took part in the survey, and says that starting with the December 2024 monthly updates it calculates generic NADACs as a three-month moving average. The 2024 NADAC file³ shows the swings directly, and our piece on the 2024 NADAC swings walks through them. Monthly moves have been calmer since, averaging 1.4 percent from January 2025 through October 2026, which is why the table above uses annual averages.

CMS says the moving average will continue "until further notice." When it ends, the index may get jumpier again. We recompute it each month on the prices page as new NADAC files are posted.