Potency of Medications Beyond Their Expiration Date
Study finds that stability beyond the expiration date is surprisingly long-term.
If you have a bathroom medicine cabinet, chances are you have some expired medications in there. Over-the-counter and prescription medications are required by the Food and Drug Administration to have an expiration date printed on the packaging and/or label. What’s unknown is at what point do people toss expired medications. For some, the expiration date is exactly that, the date that the medication “expires” and is no longer as potent. Others reason that drugs don’t lose their potency overnight, and continue to take “expired” drugs until some point in time when potency is questioned and replacement medications are obtained.
The expiration date placed on medications is only an assurance that the labeled potency will last until that time. Curious researchers found 8 expired medications with 14 different active ingredients in a retail pharmacy in their original, unopened containers. All of these medications had expired 28-40 years prior to their analysis, which makes me wonder how/where they found them but find them they did. Three tablets/capsules of each drug were tested.
The researchers found that 12 of 14 drug compounds tested were present in concentrations of at least 90% of labeled amounts (which is the level generally recognized for minimal acceptable potency). These drugs included fiorinal, codeine, pentobarbital, secobarbitol, caffeine, and 7 lesser known compounds. Two compounds (aspirin and amphetamine) were present in amounts of less that 90% labeled content. It’s probably safe to say that although this study found that certain medications have a longer than previously thought potency duration, these study findings can’t be generalized to apply to all medications. For potency assurance, it’s best to stick with the expiration date printed on the packaging and/or label.
Cantrell L, Suchard JR, Wu J, Gerona RR. Stability of Active Ingredients in Long-Expired Prescription Medications. Arch Intern Med. 2012; [online ahead of print]. Available at http://archinte.jamanetwork.com/article.aspx?articleid=1377417.