Did prescription drug prices really drop?

The index math

The CPI is an index (1982-84 = 100), so the percent change between two months is the difference divided by the earlier month, the same formula BLS shows in its technical note.

• In plain dollars: prescriptions that cost a combined $100.00 (patient + insurer) at September 2025 prices would cost about $95.52 at September 2026 prices, by this index.
• September 2026 is the lowest reading since December 2022 (534.900). The high point in the table below is Feb. 2025 (572.748); September 2026 is −5.1% from there.
• Same release, 12 months to September 2026: all items +3.7%, medical care +1.5%, medical care commodities −3.3%, medicinal drugs −3.4%, prescription drugs −4.5%.
• Seasonal adjustment: BLS marks this index “not seasonally adjusted.” Its seasonally adjusted series (CUSR0000SEMF01) carries the same values as the unadjusted one (CUUR0000SEMF01), so −1.2% is the monthly change either way.
• Weight: prescription drugs were 0.909% of the all-items CPI (relative importance, August 2026).

Sources: BLS CPI release, Sept. 2026 · BLS CPI table 2 · BLS series CUUR0000SEMF01 · BLS series CUSR0000SEMF01

Last 24 months of the prescription drug CPI

BLS series CUUR0000SEMF01 (U.S. city average, all urban consumers). Changes are computed from the published index levels and match BLS’s published one-decimal figures. October 2025 was not published (BLS: “Data unavailable due to the 2025 lapse in appropriations”), so November 2025’s monthly change and October 2025’s yearly change show n/a. Sources: BLS series CUUR0000SEMF01 · BLS CPI release, Sept. 2026

What the index measures (and what it doesn’t)

“The prescription drugs index measures price change of drugs purchased with a prescription at a retail, mail order, or internet pharmacy. The tracked price is the total reimbursement to the retailer from the patient and all eligible payers for a single prescription.” — BLS

• Total transaction price, not your bill. The price BLS tracks is what the pharmacy receives in total: your payment plus any amount paid by your insurer or Medicare Part D plan. It is not each household’s out-of-pocket cost.
• Who pays counts: eligible payers are self-pay (cash), commercial or private insurance, and Medicare Part D. Medicaid is not included.
• Rebates: manufacturer rebates paid to pharmacies or insurers after the sale are not subtracted from the prices BLS records.
• Coupons: when a coupon is used, BLS records what the consumer paid after the coupon; any extra payment to the pharmacy from the manufacturer isn’t captured.
• Hospital drugs: drugs mainly given and paid for during hospital visits are counted in the hospital services index, not here.
• Sampling: BLS picks from a pharmacy’s last 20 prescriptions, with more expensive prescriptions more likely to be chosen; brand-to-generic switches after a patent expires are reflected as price changes.
• Weights vs. prices: the index’s weight in the CPI comes from out-of-pocket spending, but its price change reflects the total reimbursement.
• No causes: the CPI reports how much prices changed, not why.

Source: BLS CPI medical care methodology (paraphrased except the quote).

What it means for you

A falling index doesn’t tell you what you’ll pay at the counter. Your cost depends on your plan’s premium, deductible, drug list and copays. If you have Medicare, the 2027 numbers on our Medicare Part D 2027 page set the limits:

• $2,400: the 2027 out-of-pocket cap on covered Part D drugs. After you reach it, you pay $0 for covered drugs for the rest of 2027.
• $700: the most any Medicare drug plan can charge as a deductible in 2027.
• About $36 a month: CMS’s projected average stand-alone Part D premium for 2027.
• Open enrollment: Oct. 15 – Dec. 7, 2026. Join, switch or drop a Medicare drug plan; the plan must get your request by Dec. 7 and changes start Jan. 1, 2027 (Medicare.gov).

15 drugs with Medicare negotiated prices from Jan. 1, 2027 (prices Medicare drug plans pay for a 30-day supply, not your copay; they start after the September 2026 data above):

Sources: VaultRubric Part D 2027 · Medicare.gov: Joining a plan. Full details, a cost calculator and plans by state are on the Part D page.

Sources & as-of dates

• BLS: Consumer Price Index - September 2026 (news release USDL-26-1574) (Oct. 14, 2026; checked 2026-10-17)
• BLS CPI detailed table 2: CPI-U by detailed expenditure category, September 2026 (Prescription drugs row) (Oct. 14, 2026; checked 2026-10-17)
• BLS series CUUR0000SEMF01: Prescription drugs, U.S. city average, all urban consumers, not seasonally adjusted (through Sept. 2026; checked 2026-10-17)
• BLS series CUSR0000SEMF01: Prescription drugs, seasonally adjusted (same values as the unadjusted series) (through Sept. 2026; checked 2026-10-17)
• BLS: Measuring Price Change in the CPI: Medical care (Prescription drugs section) (last modified Aug. 19, 2026; checked 2026-10-17)
• VaultRubric: Medicare Part D 2027 (CMS and Medicare.gov figures) (as of Oct. 16, 2026; checked 2026-10-17)
• Medicare.gov: Joining a plan (Open Enrollment Period Oct. 15-Dec. 7) (read Oct. 17, 2026; checked 2026-10-17)