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Pharmacology/Klonopin's potency/effectiveness past expiration date


Dear Dr. Cappuccilli,

Does klonopin (or any benzo for that matter) ever really expire?  In other words will it be just as effective 20 years from now as it would be today or do these things lose potency over time?


The short answer is we don't know.

You have to understand that drug companies have to do stability and safety testing to produce the drugs for human consumption.  I cannot recommend that you use a drug past its expiration date.

The reason for that is the drug companies test stability and safety for a fixed period and then they stop the test.  Drugs are rated based on those tests.  Those tests are run under normal expected conditions - any number of things can ruin your medication is weeks or months.  A simple example is keeping your drugs in prescription bottles in the bathroom medicine cabinet.  Prescription bottles are plastic and not high tech at all - nothing to absorb moisture - nothing to keep the pills from the environment - they are not airtight or water tight.  The bathroom is a moist environment - moisture seeps in and softens or dissolves tablets, makes capsules sticky and clumps powders. (incidentally don't keep your drugs in the bathroom).  So drugs kept in a vacuum sealed canister out of the light and without contamination from being touched by human hands may last years longer (but no one wants to spend the money to find out for sure).

If in date medication is available please use that instead.

If you are worried about the "real" shelf life of the pills that you are getting ask your pharmacist to show you the stock bottle they came out of - that bottle will give you a date that is (probably) 1-3 years longer than the 1 year that all prescriptions are labeled with.

If there is a zombie apocalypse keep every tablet you have because they are going to be impossible to get - hows that sound?



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Dr. Joshua Cappuccilli


I can answer most questions involving medication use, side effects, adverse effects, interactions and how drugs relate to specific disease states. No one can answer all questions; I will respond as such if I cannot provide an answer. I will provide resources / references for the information that I use to formulate the answer given.


I am a Doctor of Pharmacy currently practicing in Florida in a retail pharmacy.

California Phamacist Association American Pharmacy Assocaition

BA University of South Florida PharmD University of Florida APhA Medication Therapy Management certification

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