Medicines can outlast use by dates

In 2005, at the height of the bird flu scare, we bought a pack of Tamiflu providing 10 capsules. According to the package, its effectiveness ended in 2010. Hoffman-LaRoche has a vested interest in saying that the effective period is not too long as this would make no commercial sense. Are you aware of any studies which tested the effectiveness of medication after the due date?
J.L.
I'll ignore the bigger issue of whether your $80 pandemic investment would have been better spent on hand sanitiser, and just try to answer your very relevant question.
The US Department of defence ran into the same problem as you, but it had a lot more on the line than $80. It started a programme to test if its hundreds of millions of dollars of various stockpiled medications were good beyond their expiration dates. What the Shelf Life Extension Program (SLEP) found was that almost 90 per cent of the medications it tested remained stable even five years beyond their expiration date. The medications didn't get special treatment, but were kept in their original, unopened containers. It should also be noted that a few special medications, such as nitroglycerin, liquid antibiotics, insulin, and adrenaline, don't store well at all and need to be kept fresh and up-to-date to work effectively. But regarding Tamiflu: the SLEP tested one lot and concluded that it should be good for more than seven years beyond its expiration date.
So, if most drugs remain safe and effective well beyond their due-by dates, why would manufacturers make these dates so conservative? They say it's to guarantee consistency and effectiveness. Critics may say it's more about boosting sales. Both may be true. No one wants increased medical liability, so the advice from doctors, pharmacists, and drug manufacturers will always be to discard expired medications. But the reality is that the majority of medications kept in their original packaging will be effective for more than five years after their expiration dates, and sometimes much longer.
Gary Payinda MD is an emergency medicine consultant in Whangarei.
Have a science, health topic or question you'd like addressed? Email: drpayinda@gmail.com
(This column provides general information and is not a substitute for the medical advice of your personal doctor.)