by Michael Orr

Created on: January 29, 2009

Most pharmaceutical drugs come with an expiration date, but will they harm you if you take them anyway? The answer is yes and no. All chemical compositions break down over time, including drugs. Legally, the expiration date is the date that, under normal circumstances, the medication decays enough to fall below the labeled dosage. Keep in mind that if you keep you pills in your glove box during the heat of summer they will decay considerably faster. Therefore, for the rest of this article we will consider normal circumstances, as in keeping them in your medicine chest or cabinet.

So should you take these expired drugs or not? That depends on a number of factors. All liquid medications should be discarded after expiration as they have likely been exposed to some bacteria or other pathogen that will at best make the solution ineffective, and at worst make you ill. It also depends on the type of drug and dosing recommendations. For example, a pain killer such as Vicodin has a broad therapeutic spectrum meaning the dosage may vary depending on the intensity of the pain. Because of this if the dosage is somewhat less than the labeling says, it is probably safe for most people. The fact is that many people actually take more than prescribed doses of these drugs anyway, which can lead to addiction.

However, a narrow therapeutic-index drug, such as Synthroid (a treatment for hypothyroidism) is dosed in micrograms, mcg, where most drugs are dosed in milligrams. Because of the extremely small amounts of active ingredient in a tablet they are less stable. A patient on these type of drugs is titrated up to a specific dose. Even a small change in dosage, whether from time-decay or exposure to heat or even a generic substitute can result in abnormal levels in the system and the and throw your system out of whack. The patient will then have undergo re-titration to find the appropriate dosage again.

Clearly, most people should discard expired medications. But if you have some understanding of the drug class and or the theraputic index you can make well informed decisions about what is safe to take and what is not.

This same logic can also be used when deciding whether or not to take the generic from the pharmacy. In the Synthroid example, it's is important to realize that generic drugs, legally, can vary by 20%. This means that if you have titrated up to 100mcg of Synthroid and you chose the generic option from the pharmacist. The generic could actually be anywhere from 80mcg to 120 mcg. Synthroid has three different dosages within that range. It would not make sense then to accept the generic substitute.

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