The shelf life of drugs: longer than you think

I was cleaning out the medicine cabinet the other day and came across some prednisone that a friend had given me over 20 years ago. Prednisone is a powerful corticosteroid anti-inflammatory drug that I’ve taken to combat poison ivy. In that case, it was miraculous. Anyhow, I took one just to see what would happen. The answer: nothing. Dang. I had a newly pulled muscle plus other aches and pains to test it on. I guess 20 years is pushing it.

Maybe not. Some scientists at the California Poison Control System tested the effectiveness of eight drugs that had been sitting around unopened in pharmacies a full 28 to 40 years past their expiration dates. They used a mass spectrometer to analyze how much of the active ingredients remained in the pills. Of the 14 active ingredients, 12 were still at a high enough concentration to qualify as “acceptable potency.” Some of these ingredients included acetaminophen, codeine, hydrocodone, methaqualone (Quaaludes!), and caffeine. Aspirin as an active ingredient didn’t make the cut. 

At any rate, many drugs are just fine after their expiration date. The expiration date on a drug is usually one to five years after it was manufactured. But those dates are often set arbitrarily. The FDA doesn’t require pharmaceutical makers to test how long the active ingredients will last. So basically, they don’t really know.

The poison control researchers are all for extending expiration dates for many drugs. In fact the Shelf Life Extension  Program (SLEP) does just that for drugs in federal stockpiles. The program, which is administered by the U.S. Department of Defense in cooperation with the FDA, acknowledges that the actual shelf life of drugs may be longer than their stated expiration date. They allow drugs in federal stockpiles to be retained for up to 278 months if tests show they are still potent. Some of the ingredients remained good for 480 months—so far.

The most important implications of the study is the cost savings. As one of the researchers said, “Given that Americans currently spend more than $300 billion annual on prescription medications, extending drug expiration dates could yield enormous health care expenditure savings.” Kind of a no-brainer.

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