I got interested in this site after looking up information on tetracycline class antibiotic expiration dates.
There were some very informative answers to the question but no one had an answer.
I found this on Wikipedia, “Minocycline, like all tetracyclines, becomes dangerous past its expiration date. While most prescription drugs lose potency after their expiration dates, tetracyclines were known to become toxic over time due to the breakdown of certain chemicals present in the manufactured capsules. This is not a present concern in drugs manufactured in developed countries. Expired tetracyclines, as previously manufactured, can cause serious damage to the kidneys.”
Note the, " THIS IS NOT A PRESENT CONCERN IN DRUGS MANUFACTURED IN DEVELOPED COUNTRIES."
I guess I should throw out my Oracae expired on April 2011 just to be safe but I can’t help feel that it is a waste.
It’s not a concern in drugs manufactured in developed countries because these countries do stability testing. It’s part of the drug approval protocol to get it on the market, and lots of drugs are continually tested for as long as the drug is manufactured and sold. If a lot “goes bad” and fails stability testing, it gets recalled.
The thing is, a typical stability protocol is 3 years or so, and while the large amount of data collected shows that the drug is within acceptable limits during the shelf life/expiration time assigned to it, it doesn’t mean that some degradation isn’t happening. On day 1 it could be at 101.4% of label strength and on the last day at 98.7% of label strength and both of those still pass stability. 97.8% wouldn’t (in most cases…some drugs have a slightly wider range of allowable potency). When the drug degrades, the various products it becomes might be harmless or harmful, and some in very small quantities. I’ve seen degradation product limits in the range of No More Than 0.1% of the active amount, which isn’t really a lot, but there’s reason to believe (or know) that that degradation product is unsafe for patients.
There’s obviously a buffer region between the data collected during stability studies and the date range on the bottle. It’s also just as obvious that drugs aren’t a time bomb. If something was safe in “April 2011” that generally is considered to be the last day of the month anyways (on paperwork), and obviously the drug is not immediately toxic on May 1st. And not on May 2nd. And probably not on May 31st. But maybe on September 1st? Who knows?
That’s the catch; beyond the legally required data obtained during stability there is no data whatsoever to know how the drug behaves past the required timeframe. No company studies it because no law requires them do, and they aren’t going to waste their money on very expensive tests that aren’t required. There simply is no way whatsoever to accurately predict when the drug will go from “still safe” to “kinda risky” to “it’s gonna kill you” (assuming it could get that bad!) Just like you don’t know quite when the old milk in your fridge goes bad, but you know it does. Sure, you can smell it with milk, and you could test a drug and compare it to it’s potency/impurity requirements, but those are destructive tests and you wouldn’t have the pill anymore. And again, no pharmaceutical company in the world tests beyond what is legally required of them. The FDA/TPD/etc could require longer stability protocols - but you’d still have an expiration date reflecting that obtained data and we’d simply be discussing why drugs expire after 5 years and not 3 or whatever.