Unit-dose and blister packaging, from hospital carts to dose packs

In January 2026, a company recalled 3,456 cartons of methylprednisolone 4 mg tablets sold in a 21-tablet dose pack. Nothing was wrong with the tablets. The printed foil had been applied to the blister card in the wrong orientation, "which results in incorrect dosing information when following the directions on the foil," according to FDA's enforcement record¹. FDA classed it Class II.

The case shows how much work a blister card does. In a dose pack, the package is also the instruction sheet, the calendar and the label for every single tablet. In hospitals, the same idea, one dose sealed and labeled on its own, has been the standard way to deliver oral medicines since the 1990s.

Behind both sits a set of federal labeling rules, a decades-old limit on how long a repackaged dose may be dated, and a child-resistant packaging law that treats a single blister differently from a bottle. FDA's recall records show what happens when any of it goes wrong.

How hospitals moved to unit dose

Before unit dose, hospital nursing units kept drugs in bulk bottles, and a nurse counted out each patient's doses onto a tray. Studies of that system found error rates of up to 10 percent when what was ordered was compared with what was given, according to a 2018 review in Frontiers in Pharmacology² by Philip J. Schneider. The unit-dose system moved dispensing to the pharmacy, which sent each patient a supply of 24 hours or less in individually packaged and labeled doses. It "was shown to reduce medication errors by as much as 50%," the review says.

Evidence for the system was published in 1968, and adoption took decades. The review, drawing on national surveys of hospital pharmacy, traces the spread of unit dose and the technologies that followed it.

Source: Schneider PJ, Frontiers in Pharmacology (2018), citing national hospital pharmacy surveys.

Bedside scanning only works if each dose carries a barcode. FDA's 2004 bar code rule, effective April 26 of that year, required a linear barcode containing at least the National Drug Code on the labels of prescription drugs, with some exemptions, and of over-the-counter drugs commonly used in hospitals, according to the Federal Register notice³. FDA estimated net benefits of $3.4 billion to $3.6 billion a year and the avoidance of more than 500,000 adverse drug events and transfusion errors over 20 years. FDA said a unit-of-use package, as the drug's immediate container, must carry the barcode itself. It declined requests to make manufacturers use unit-dose packaging, saying its industry contacts suggested those decisions "depend more on market demand than on bar code costs." Our piece on the NDC number explains the code inside that barcode.

What FDA requires on a unit-dose label

FDA's compliance policy guide on unit-dose labeling, issued in February 1984 and still posted, defines the unit-dose container as "a non-reusable container" holding a single dose for administration directly from the container, "employed generally in a hospital unit dose system." It treats each one "as a drug in package form subject to all requirements of the Act," according to CPG Sec. 430.100⁴.

Under that policy, the label on each prescription unit dose must carry the established name and strength, the expiration date, the lot or control number, the name and place of business of the manufacturer, packer or distributor, and required statements such as "Refrigerate" or "Protect From Light." The NDC is recommended, not required. The outer box must state how many unit doses it holds and carry the prescription legend.

FDA's 2022 guidance on container labels adds design advice for blisters. Lot number, expiration date and barcode should appear over each blister cell "so that this important information remains available to the end user up to the point at which the last dose is removed." Each cell should hold one tablet or capsule, the barcode should not cross a perforation, and because foil is reflective, "a nonreflective material should be used" when possible, the guidance says⁵. For liquids in unit-dose cups, strength should be stated as the total in the cup, such as "40 mEq per 30 mL," because, the guidance says, a label reading 20 mEq per 15 mL on a cup that holds 30 mL can cause confusion.

The six-month rule for repackaged doses

Some unit doses come from repackagers that move a manufacturer's bulk tablets or capsules into single-dose containers. Federal rules require stability testing to support any expiration date, and the repackaged product sits in a different container from the one the manufacturer tested. FDA's answer is a policy of enforcement discretion, updated in a July 2020 guidance on unit-dose repackaging⁶.

FDA generally will not take action over a missing stability study if a repackaged solid oral dose carries an expiration date no later than six months from repackaging or 25 percent of the time left on the manufacturer's date, "whichever time period is shorter." Five conditions apply: the container meets the Class A or Class B standard in USP chapter 671; it gives at least the light protection of the original; the original bottle had not been opened and is repackaged in one operation; storage matches the original labeling; and the labeling does not caution against repackaging. Longer dates are possible with supporting data. The guidance covers commercial repackagers; state-licensed pharmacies, federal facilities and outsourcing facilities fall under a separate 2017 guidance.

Source: GxRadar arithmetic applying FDA's July 2020 guidance, Expiration Dating of Unit-Dose Repackaged Solid Oral Dosage Form Drug Products.

Those six-month and 25 percent figures go back decades. FDA's 1984 policy guide⁴ set the same two limits, with an exclusion for antibiotics and sublingual nitroglycerin. More on how manufacturers set the original date is in our explainer on drug expiration dates and shelf life.

Blisters, dose packs and child-resistant law

Outside hospitals, blister cards and calendar packs are used for products such as oral contraceptives and steroid dose packs. FDA's 2022 guidance says such packs "may improve patient adherence and minimize the risk of accidental exposure to the drug," and warns that a confusing design can itself lead to error, the risk the January 2026 dose pack recall made concrete.

Anything dispensed for home use generally falls under the Poison Prevention Packaging Act, which covers oral prescription drugs. A single-unit package must stop at least 80 percent of test children, the standard set for "unit packaging" in 16 CFR 1700.15⁷, against 85 percent (80 percent after a demonstration) for other special packaging. Hospital unit-dose packages are not always child-resistant, and FDA's 2022 guidance recommends a carton statement when they are not: "This package is not child-resistant. If dispensed for outpatient use, a child-resistant container should be used."

Some dose packs are exempt by name. The list in 16 CFR 1700.14(a)(10)⁸ includes cyclic oral contraceptives in manufacturers' "mnemonic (memory-aid) dispenser packages," prednisone tablets in packages holding no more than 105 mg, and methylprednisolone tablets in packages holding no more than 84 mg. A 21-tablet pack of 4 mg methylprednisolone tablets holds 21 × 4 = 84 mg, exactly the cap.

When blister packaging fails

GxRadar searched 18,076 drug recall records in FDA's openFDA enforcement data¹, 2012 through Oct. 28, 2026, for reasons that mention blisters or unit doses. It found 77 records, 11 of them Class I. The busiest year was 2016, with 15. Several recent ones involve seals. In June 2025, a company recalled 23,232 cartons of gabapentin 100 mg capsules in 10-by-10 blister cartons for a "defective container; blister packaging inadequately sealed," FDA's record shows¹. A recall of 8,892 cartons of midodrine tablets in blister packs followed in February 2026 for the same reason.

Other failures run the other way, with a correct blister inside a wrong box. In several Class I recalls posted in 2024 and 2025, cartons of an orally disintegrating tablet were labeled with the wrong strength while "the blister strips inside the product carton reflect the correct strength." Our recall tracker groups all recall reasons by year, and our guide on reading a prescription label covers what a pharmacy adds when it dispenses a pack.

Blisters also complicate drug tracing. Under the Drug Supply Chain Security Act, the barcoded product identifier goes on the smallest unit a manufacturer intends to sell to a pharmacy, and FDA's 2021 product identifier guidance⁹ says that if a wholesaler might foreseeably sell the 10 units inside a carton one by one, manufacturers "may want to apply a product identifier to each of the 10 product units." The recalled methylprednisolone dose packs carried an expiration date of November 2026.