Joshua asked
Can you take expired Tylenol?
Answer
As a general rule of thumb, it is not recommended to take expired Tylenol (acetaminophen), or any any medication that is past the manufacturer set expiration date for that matter.
The reason for this recommendation is that is nearly impossible to tell if the medication will be as potent as it once was without testing it. A manufacturer will perform stability tests on their products to determine an appropriate expiration date. The stability tests are performed for a finite time period, usually two to three years. After this period of time, there isn't any data to indicate whether or not the drug is stable. In other words, the expiration is marked for however long the manufacturer has data for.
While manufacturers could theoretically do stability tests for longer periods of time, they don't really have any financial incentive to do so. In addition, most medication is consumed within a few years time so longer tests are unnecessary.
Having said all that, most data suggests that it takes a significant amount of time for a drug to "go bad", or lose a large percentage of its original potency.
One of the largest studies in this regard was done in the 1980's. The FDA (Food and Drug Administration) did a study testing the potency of expired drugs the military had on hand. They found that the vast majority of drugs had around 70-80% potency after 10 years if stored in the original container!
Back to the expired Tylenol. It most likely is safe to take and may provide similar effectiveness to non-expired products, but there is just no way to definitively know. There could be additional factors at play such as how it was stored throughout its shelf life and exposure to air/humidity etc... Since Tylenol is available over the counter and is inexpensive, it makes more sense to buy a non-expired replacement.