Do drugs really lose their potency and if they do are they really a danger to us? The recent decision by the FDA to extend the shelf life of EpiPens beyond what is on the label has challenged conventional thinking about the long-term safety of stored drugs – and it’s about time.

Unfortunately, there is very little evidence about the shelf life of many drugs. The recent stockpiling of vaccines in the UK in anticipation of post Brexit shortages is also a cause for concern.

US legislation which is determined by the FDA, seems to contradict its own evidence about extended shelf life of drugs.

Half century ago, kidney damage was reported from an out-of-date antibiotic, tetracycline.  That drug is no longer on the market but it still preoccupies our thinking. Many respectable sources recommend safely disposing of drugs that are out of date. However, it is difficult to find any scientific evidence to back up that assertion beyond traditionally accepted wisdom. For example, drugs in liquid forms (e.g. solutions and suspensions) are not as stable as those in the solid forms (e.g. tablets and capsules). Improper storage of a medication (e.g. exposure of a medicine to oxygen, light, heat, and/or humidity) may result in losing its full potency and/or safety before the printed expiration time on that product.

Now the US military and the FDA suggest otherwise. They both maintain large stockpiles of drugs and are able to test long term efficacy and safety. The US military tested more than 100 drugs of their stockpiled drugs and found that 90% of them, both prescription and over-the-counter, were perfectly good to use even 15 years after the expiration date.

The FDA also stockpiles drugs and tests their long-term efficacy. The Shelf Life Extension Program (SLEP), run by the FDA was developed essentially for global emergencies such as natural disasters and waring regions. It is a stockpile of more than $7 billion worth of medicines and medical supplies mainly consisting of antibiotics, chemical antidotes, antitoxins, vaccines, and antiviral drugs. There are no biological agents such as are used mainly in oncology. From the over 300 stockpiled drugs the FDA tested, 88% of them remained stable for an average of 66 months past their original expiration date, as long as they were stored in appropriate conditions in their original sealed container.

lt’s difficult to know what to make of these data when, US legislation which is determined by the FDA, seems to contradict its own evidence. The US law requires drug manufacturers to label their products with expiration dates beyond which full potency and safety cannot be guaranteed.

Of course, not all drugs are stockpiled in the safe conditions of the FDA and legislation must mitigate for circumstances beyond its control such as improper storage of a medication (e.g. exposure of a medicine to oxygen, light, heat, and/or humidity) which may result in losing its full potency and/or safety before the printed expiration time on that product.

With rising pharmaceutical costs, it is even more important ensure that drugs are used in the most effective way – to their maximum efficacy. Everyday drugs, which are not stockpiled, should undergo the same long-term efficacy testing.