Can You Take Expired Gabapentin?

In our latest question and answer, the pharmacist discusses whether or not it is safe to take expired gabapentin.

Dec 17, 2017

C.C. asked

Is it safe to take gabapentin 100mg capsules that expired in 2016?


Gabapentin is an anti-convulsant that works directly on nerves. It affects chemicals and nerves in the body to treat seizures and certain types of pain like nerve pain like diabetic neuropathy or post-herpetic pain caused by the herpes or shingles virus (herpes zoster). Gabapentin also is used to treat restless leg syndrome and seizures in those at least 3 years old. Gabapentin is likely to cause dizziness and drowsiness.

Generally speaking, if not otherwise labeled, prescription medications are considered expired one year after dispensing to a patient. In the case of your gabapentin, it would be considered to be expired as it has been over one year from the time it was dispensed to you.

The answer of whether or not it is safe to use expired gabpentin is a little more complicated than a simple "yes" or "no" answer. 

In the United States, law mandates that at the time of expiration, a drug must be at least 90% of its original potency. That is our concern when we look at a drug's expiration it as effective as it once was (when it was originally manufactured and kept under normal storage conditions)? Very rarely is safety a concern with expired medications as it is uncommon that medications will "go bad" to the point of causing illness. Some medications are rarely associated with this (e.g. tetracycline), but gabapentin is not.

Most drugs, labeled in original bottles, will expire two to five years from the date of manufacture. A company will often perform stability tests for a finite time period. For example, if a manufacturer wants to set an expiration date at 3 years, they perform tests on the drug up to and including that time period, but not beyond. The drug may very well still be within the acceptable potency range beyond that date, but there is no data to verify. 

In other words, the date on a manufacturer's bottle is an assurance to a pharmacy (and customer) that the drug will maintain its potency until AT LEAST the listed expiration date when stored under ideal storage conditions. Some studies show that drugs will maintain 90% of their potency for a minimum of 5 years after their expiration date

In a retail setting, most states don't require the prescription bottle to list the expiration date of the drug from the 'stock' bottle. This is due to mostly to two factors:

  • It is too cumbersome to record the manufacturer expiration date of every fill of medication. Most pharmacy software isn't at the point where this is possible. In the future however, enhanced bar code scanning may make this a possibility.
  • The storage conditions of dispensed medications are often not ideal. Very often they are left at too high or too low of a temperature, are not stored in an airtight container or are stored in humid conditions (e.g. the bathroom).

Due to the above reasons, many states simply require a listing of an expiration date of one year after dispensing, even if the manufacturer's bottle states a later date. So your bottle of gabapentin 100mg may have had an expiration date of 2017 or 2018, but the dispensed bottle may list 2016.

In regard to gabapentin specifically, it is a capsule dosage form, which is considered one of the most stable dosage form post-expiration date. Liquids (like reconstituted antibiotic suspensions) are not considered stable at all and should not be used post-expiration date.

One of the most important factors in the stability of drugs is how they are stored. Factors that can affect the stability and efficacy of medications are light, air, moisture, and temperatures (too hot or too cold). How do the tablets/capsules look? Do they appear wet in nature? Do they still look solid in form or are they crumbling? Are they in the air tight container they were dispensed in? Do they have an unusual odor? Even if there are no signs the drug has degraded, there really is no way to definitively tell once the expiration date had passed.

It is advised that you NOT take expired medication. It has been more than a year beyond the dispensed date and is thus considered to be expired. The medication should be disposed of as there is a chance that it won't have the required efficacy needed. If you are in need of another prescription, please reach out to your doctor.


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