Posted by Cam W. on August 29, 2001, at 16:59:26
In reply to expired meds, posted by Shelley on August 29, 2001, at 14:24:54
Shelley - A tablet starts to degradate as soon as it is made. To compensate for this (and to follow Health Canada/FDA laws), drug companies are allowed batches of drugs to have a potency between 95% and 105% of stated drug weight. Most drug companies will manufacture their medications with slightly more than 100% of stated dose, so that the drug's extends time to expiry date, slightly.
The expiry date is determined by chemical testing and is reached once a drug still contains 95% active drug. Most drugs are safe to use after their expiry date, but how it effective (and potent) it will be can vary greatly. How much of the actual drug is left can only be determined by having the drug tested. Factors, such as: how the med was stored (on your shelf, in the pharmacy, and at the wholesaler); or how long the med was on the pharmacy shelf (unless there is an actual expiry date on the presription bottle). Excessive heat and cold can both degradate tablets faster, as can humidity.
Tegretol™ (carbamazepine) blood levels are monitored, because the drug has a narrow therapeutic window (which means that the blood level needs to between effective minimum effective concentration and toxic concentrations, is more narrow than most other drugs). For this reason, I would less likely to use a drug like Tegretol after it's expiry date, than many other medications.
Also, a year after expiry date is a little long, and it would be very difficult to guess how much active ingredient is left.
My thoughts - Cam
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poster:Cam W.
thread:76830
URL: http://www.dr-bob.org/babble/20010828/msgs/76849.html