Are Epi-Pen Expiry Dates Accurate? — Chromatography Explores

We’ve all probably got some out of date medicines in a back of a cupboard at home or buried in a drawer — the junk drawer that contains a thousand things you might just need one day. Usually it is just a few pills left over from chest infection that we stopped taking when we felt better. The NHS is quite explicit in their advice on taking medicines after the expiry date. Don’t.

Increasing costs put health at peril?

But what if that medication is needed to save your life in an emergency? For people at risk of anaphylaxis — a severe allergic reaction to insect bites or stings, food or other allergen — an EpiPen is a critical piece of kit. In the US, the price of an EpiPen has increased by over 400% since 2007 angering patients — even the Federal Drug Administration has got involved to review the price. So, it is understandable that cash strapped patients might be tempted to keep hold of them for longer than a year. But are they safe to use?

Anaphylaxis and anaphylactic shock

An EpiPen is simply a device that delivers an injection of epinephrine, commonly known as adrenaline in the UK. Epinephrine is a hormone that our bodies produce in the adrenal glands and plays a key role in our fight or flight response. When someone suffers from a severe life threatening allergic reaction — known as anaphylaxis — as well as itching and redness, the patient’s airway might be affected and they might struggle to breathe. If their blood pressure drops, blood flow to their key organs might be disrupted — this is known as anaphylactic shock. Not every person experiences shock when they suffer a severe allergic reaction.

When someone has a life threatening allergic reaction, the first thing to do is inject an EpiPen into their thigh. This releases epinephrine which works to constrict blood vessels leading to increased blood pressure and relaxes the smooth muscles in the lungs reducing wheeziness and helping the patient to breathe. But will an out of date pen work just as well?

Should you pension off your EpiPen?

A recent study published in the Annals of Internal Medicine examining the potency of EpiPen’s up to 50 months after their expiration date. The team collected EpiPens that varied between one and fifty months past their expiration dates. They analysed the contents for colour changes and epinephrine concentration using liquid chromatography – tandem mass spectrometry. The use of liquid chromatography to analyse inhalers is discussed in the article, Method Development and Validation of Simultaneous Determination of Related Substances for Salmeterol Xinafoate and Fluticasone Propionate in Dry Powder Inhalers.

The study found that none of the samples had changed colour and that the concentration of epinephrine was 90% of the stated amount in 65% of the pens. The authors suggest that in view of the results the expiration dates should not be ignored, but that expiration dates should be revisited. Watch this space.