The brand-generic gap in NADAC

In the federal drug cost file dated Oct. 28, 2026, pharmacies paid an average of $8.69 for a single brand-name amlodipine 5 mg tablet. The generic version of the same tablet cost them about one cent, according to the CMS National Average Drug Acquisition Cost (NADAC) data¹. The brand cost 857 times as much.

That gap is unusually wide, but it is not rare. GxRadar pulled every brand-classified row in that week's file that also carried a price for the matching generic. For brand-name tablets and capsules, the median brand price was 21 times the generic price.

The numbers matter because most state Medicaid programs tie the ingredient cost they pay pharmacies to NADAC, according to CMS's state reimbursement table for the quarter ending September 2026¹⁰, and because the size of the gap says a lot about how much competition a drug faces.

Where the comparison comes from

Each weekly NADAC file lists a per-unit price for each national drug code, plus a column showing whether CMS treated that NDC as brand ("B") or generic ("G") when it set the rate. For brand drugs that have generic competition, the file adds a second figure. The field is named "Corresponding Generic Drug NADAC Per Unit," and the NADAC data definitions³ describe it as the generic rate assigned to a multiple-source brand NDC. CMS's December 2024 methodology⁴ says the corresponding generic rate can be the rate for an authorized generic when that is the only generic available.

We queried the data.medicaid.gov² datastore for the Oct. 28, 2026 file, keeping rows with classification "B" and a non-empty corresponding generic field. That returned 954 brand NDCs, covering 659 distinct product descriptions, out of 2,254 brand-classified NDCs in the file. To confirm which generic each brand row pointed to, we matched its corresponding generic price and effective date against the generic rows in the same file.

The gap for common molecules

Source: GxRadar analysis of the CMS NADAC file dated Oct. 28, 2026. Brand rows classified "B" with a corresponding generic NADAC; multiples rounded. Prices are per tablet or capsule.

Brand prices for these molecules sit between about $1 and $19 a tablet, while generic prices sit between one and 11 cents. The multiple is driven mainly by how far the generic has fallen.

Brand pricing also tends to be flat across strengths. For rosuvastatin, the file lists the brand at about $8.81 per tablet for 5 mg, 10 mg, 20 mg and 40 mg alike. The generic rises with strength, from 3.2 cents for 5 mg to 6.9 cents for 40 mg, so the multiple runs from 279x at the lowest strength to 127x at the highest.

Levothyroxine is a special case. Several branded versions appear in the file, and their NADACs for the 50 mcg tablet range from $0.85 to $4.18 against a generic rate of four cents, multiples of 21x to 104x. The levothyroxine page tracks the generic 50 mcg rate.

Where the gap narrows

Across all 659 brand products with a matched generic, the median multiple was 13x. About 19 percent were at least 100 times the generic price, and about 20 percent were less than twice it. Fourteen brand products were cheaper per unit than their corresponding generic.

Dosage form explains much of the spread. The median multiple was 21x for products priced per tablet or capsule, 2.0x for products priced per milliliter and 1.6x for those priced per gram, such as creams and some inhalers.

Source: GxRadar analysis of the CMS NADAC file dated Oct. 28, 2026. An NDC count is a rough proxy for competition, since one manufacturer can list several package sizes.

Lamotrigine shows the effect within a single molecule. The plain 25 mg tablet has 21 generic NDCs in the file and a generic price under three cents, and the brand costs 381 times as much. The extended-release and orally disintegrating versions have eight and nine generic NDCs, generic prices of 67 cents and $1.59, and much smaller multiples. Esomeprazole splits the same way, with 53 generic NDCs for the 20 mg capsule and four for the 20 mg packet. Inhaled combinations such as fluticasone-salmeterol belong to the group of complex generics, and this one has four generic NDCs and a multiple under three.

That fits federal research on how prices fall as competitors enter. In a December 2019 study⁵, FDA economists found that a single generic maker priced its product 39 percent below the pre-generic brand average manufacturer price, two makers 54 percent below, four makers 79 percent below, and six or more makers more than 95 percent below. An ASPE analysis of Medicare data published in January 2025⁶ found prices 70 to 80 percent below the pre-entry level two to three years after first generic entry in markets with 10 or more competitors. Counts of approved generic applications for any molecule can be checked in FDA's Drugs@FDA data⁹ and on GxRadar's approvals page.

What the gap leaves out

NADAC is built from pharmacy invoices. CMS's methodology says discounts or rebates that do not appear on the invoice at the line-item level are not counted. Brand manufacturers pay substantial rebates to Medicaid. For most brand drugs the basic rebate is the greater of 23.1 percent of average manufacturer price or the difference between that price and the "best price," compared with 13 percent for generics, according to a KFF explainer published March 13, 2026⁷. Commercial rebates are not public. CMS likewise says its Part D spending figures do not reflect manufacturer rebates⁸. Brand NADACs therefore overstate what payers ultimately spend on brands, and the true net gap is narrower than the invoice gap, by an amount no public dataset shows.

NADAC also reflects only chain and independent retail community pharmacies, and it is a national average. A patient's cost depends on the plan, the pharmacy and whether the brand is covered at all. Explainers on what NADAC measures, on how generics and brands differ and on therapeutic equivalence codes cover the related questions, and decisions about brand versus generic belong with a pharmacist or prescriber.

For the generic side of the ledger over time, see the GxRadar generic price index and what pharmacies pay for a month of common generics. CMS posts a new NADAC file every week on data.medicaid.gov¹, and the brand and corresponding generic figures can shift with each one.