Nitrofurantoin and the antibiotic price story

In January 2014, retail pharmacies paid an average of $1.77 for a single 100 mg capsule of nitrofurantoin monohydrate/macrocrystals, a urinary antibiotic, according to the federal government's weekly drug cost survey. In October 2026 they paid 28 cents. Ten capsules went from $17.72 to $2.84.

Nitrofurantoin is one of six oral antibiotics GxRadar follows in CMS's National Average Drug Acquisition Cost (NADAC) data¹, and it fell further than all but one of them. The six took very different paths. Three got markedly cheaper, ciprofloxacin ended a little below where it started, and two, amoxicillin and cephalexin, cost pharmacies more in 2026 than in 2014.

The split lines up closely with where new generic makers entered the market. It also sits next to a long federal argument that very low prices for old generics make supply fragile, a concern FDA has tied directly to drug shortages.

Six antibiotics, 13 years of prices

Source: GxRadar analysis of CMS NADAC weekly files. Annual averages of monthly medians of weekly generic rates; the last column compares the January 2014 and October 2026 months.

Doxycycline's fall is the largest in GxRadar's entire 43-drug price index. Its 2014 price was itself the product of a spike. HHS analysts wrote in a January 2016 brief⁴ that doxycycline had been in shortage and that "in early 2013 when there was supply disruption resulting from one manufacturer experiencing manufacturing problems, the pricing was increased." The January 2014 NADAC file² priced the capsule at $3.35. It dropped below $1 in 2016 and has stayed between about 10 and 16 cents since 2022. Our doxycycline price history has the month-by-month record, and the broader episode is covered in our piece on the generic price spikes of 2013 to 2015.

Azithromycin rose for a while, peaking at 69 cents a tablet in May 2018, before falling to about 27 cents in 2026. Ciprofloxacin wandered between 11 and 25 cents and ended slightly below its starting point.

Nitrofurantoin's long slide

Nitrofurantoin did not have a single collapse. Its NADAC fell almost every year, from about $1.73 in 2014 to $1.23 in 2016, 77 cents in 2018, 63 cents in 2020 and 45 cents in 2022 and 2024.

Then came a step down. Between October and November 2024 the capsule's NADAC fell from 46 cents to 30 cents, a 34 percent drop. Every drug in our basket fell that month, a swing that CMS's December 2024 methodology³ links to changes in how many pharmacies answered its survey, but the basket as a whole fell 13 percent. Nitrofurantoin did not bounce back. It averaged 32 cents in the first ten months of 2026.

Competition data from FDA show where some of that pressure came from. In Drugs@FDA⁵, the three oldest generic applications for nitrofurantoin monohydrate/macrocrystals capsules date to 2004 and 2005. Nine more were approved from 2015 onward, with one each in 2015, 2017 and 2018, two in 2022, three in 2023 and one in 2026. The NADAC file listed eight generic NDCs for the capsule in January 2014 and 13 in October 2026.

Where new competitors went

A similar pattern shows up across all six drugs. The table counts generic NDCs in the first January 2014 file and the last October 2026 file, and original generic approvals since 2014 for each drug's dosage form in FDA's application data.

Sources: GxRadar analysis of CMS NADAC files dated Jan. 8, 2014, and Oct. 28, 2026; openFDA Drugs@FDA bulk data (original ANDA approvals with at least one product of that ingredient and form). NDC counts include multiple package sizes and are a rough proxy for the number of suppliers.

All three drugs that got much cheaper drew new applications and gained NDCs. Amoxicillin and cephalexin drew almost none and lost NDCs, and their prices drifted up. This is a small sample and correlation is all it shows, but it matches federal research. In a December 2019 study⁶, FDA economists found that generic prices keep falling as each additional maker enters, reaching more than 95 percent below the brand price with six or more. GxRadar's approvals page tracks new generic approvals by year.

Shortages and the low-price trap

Low prices can leave supply thin. FDA's 2019 report Drug Shortages: Root Causes and Potential Solutions⁷ examined 163 drugs that went into shortage between 2013 and 2017 and found that 67 percent had a generic version on the market. In the year before the shortage, the median price for the orally administered drugs in that group was $2.27 per unit.

The report's first root cause was a "Lack of Incentives to Produce Less Profitable Drugs." It said manufacturers of older generics "face intense price competition, uncertain revenue streams, and high investment requirements." It added: "Current contracting practices contribute to a 'race to the bottom' in pricing." Our explainer on why drug shortages happen goes through the other causes.

Antibiotics have been part of that story. Amoxicillin oral powder for suspension, which pharmacists mix into a liquid, ran short in late 2022 and into 2023, a period covered in our account of the amoxicillin shortage. That is a different product from the capsule in our data. The capsule's NADAC did rise in 2023, from 7.1 cents in March to 10.2 cents in November, and peaked at 10.6 cents in March 2024. The NADAC files cannot say why.

None of the six products in our table is on FDA's current shortage list. According to the openFDA drug shortages data⁸ as of late October 2026, seven anti-infective drugs were in current shortage, and five of them were injectable products. That share fits a broader pattern covered in why sterile injectables dominate shortage lists. The full list is on GxRadar's shortage tracker.

What to watch

FDA's list also carries discontinuation notices, which flag a manufacturer's plan to stop making a specific product. In 2026 those included notices for an azithromycin tablet (posted April 9), a doxycycline hyclate tablet (Jan. 12), a delayed-release doxycycline hyclate tablet (July 30) and nitrofurantoin oral suspension (April 10). A single discontinuation in a market with many suppliers rarely moves prices much. In a thin market it can.

Nationally, the shortage count has fallen. FDA's report to Congress for calendar year 2025⁹ counted four new drug shortages that year, against a peak of 251 in 2011, and said the agency helped prevent 330. FDA posts updates on its drug shortages page¹⁰, and GxRadar's antibiotic drug pages update as each NADAC file is published.