Expired Medicines: What Actually Happens After the Date

The box of painkillers expired in March, the eye drops were opened who knows when, and the adrenaline pen in the bag went out of date last year. Nothing happens at midnight on the expiry date: it is the last day on which the manufacturer guarantees that the product, stored as the label says, is safe and as strong as printed. After that there is no guarantee — and how much that matters depends entirely on which medicine it is and what a shortfall would cost.

When to see a doctor

Right away: signs of anaphylaxis — swelling of the throat or tongue, trouble breathing, wheezing, a hoarse voice, faintness, cold or blue-grey skin (NHS, UK). Use the adrenaline auto-injector — an expired one if no in-date pen is at hand and the solution in the window is clear, not pink or brown, cloudy or with particles; call the emergency number (112 in the EU and Russia, 911 in the US, 999 in the UK); lie down and raise the legs, or, if breathing is hard, raise the shoulders or sit up slowly; if there is no improvement after five minutes, use a second pen (NHS). Also right away: sudden confusion, trouble breathing or seizures after taking anything.

The same day: you took an expired medicine and nausea, pain or a rash followed; you are not sure whether a treatment is working.

Routinely: a prescription medicine you take every day has expired — replace it rather than finish it; for any specific product, the pharmacist is the right person to ask.

What is happening

What the date means. The FDA (US): an expired product can be less effective or riskier because of a change in chemical composition or a loss of strength; sub-potent antibiotics can fail to treat an infection and drive resistance; some expired medicines can grow bacteria. Store in a cool, dry place, not the bathroom, away from children.

Many tablets hold up longer than the date. In one analysis of sealed medicines that had expired 28 to 40 years earlier, 12 of 14 compounds still contained at least 90 percent of the labeled amount; aspirin did not (Cantrell et al., 2012). That is a finding about those stored samples, not a licence: safety was not tested, and the authors do not recommend taking expired drugs.

Where a shortfall is dangerous. Insulin, nitroglycerin, adrenaline and antibiotics are the textbook cases: a weaker dose there is a treatment that fails at the moment it is needed. Adrenaline auto-injectors 1 to 50 months past their date all held at least 80 percent of the dose, and at least 90 percent in 65 percent of adult pens and 56 percent of children's pens; the authors' conclusion was that in anaphylaxis, with nothing else at hand, an expired pen beats no pen (Cantrell et al., 2017). The label adds the check: if the solution has turned pink or brown, cloudy or has particles, replace it.

Degradation can produce something new. Degraded tetracycline from old formulations caused Fanconi syndrome, a kidney injury, in case reports from 1963 onward. Modern formulations differ, but it is the reason "expired" does not only mean "weaker."

An opened bottle has its own clock. Insulin kept out of the fridge, opened or not, stays effective for up to 28 days at 15–30 °C for typical products (FDA, US), but each product's leaflet sets its own in-use period; never use insulin that has been frozen. Chloramphenicol eye drops in the UK: four weeks after opening, in the fridge (NHS). Nitroglycerin: in its original container, tightly closed, away from heat and moisture; it may work less well after some time (MedlinePlus).

What to do

Sort by consequence, not by date alone. Ask what a weaker dose would cost: for an antibiotic, insulin, a heart medicine or adrenaline the answer is a treatment that fails, so replace them; for anything else, a pharmacist's answer beats a guess.
Write the opening date on bottles, drops and creams. The in-use period is in the leaflet.
Move the cabinet out of the bathroom and the kitchen heat.
Dispose of it properly. US: take-back sites at pharmacies and police stations, mail-back envelopes, the FDA flush list for the few medicines dangerous in a single dose, and otherwise the trash: mixed with coffee grounds or cat litter in a sealed bag, personal details scratched off. UK: back to any pharmacy, free — not the bin, not the toilet. Germany: household waste in most municipalities, some pharmacies take returns voluntarily, never the toilet or the sink; check by postcode at arzneimittelentsorgung.de. Spain: the SIGRE container at the pharmacy. Portugal: Valormed at the pharmacy. Russia: we found no nationwide take-back for households; eco-centres and some pharmacy chains collect in a few cities, otherwise household waste by the same rules, never the drain.
Check the kit on a schedule, as what should be in a home first aid kit suggests. Unlike food, medicines have no "best before": the difference is explained in expiry date versus best before.

When this is not the case

Supplements expire too, and lose potency the same way; see supplements without a test. And a medicine that looks fine but was stored in a hot car or a steamy bathroom may be worse than an expired one from a cool drawer: the date assumes storage as labelled. The map of the cabinet: the active ingredient.

Sources

Checked: September 7, 2026