When does tizanidine(zanaflex) 4mg expire?

The United States Government decided to do testing on many drugs regarding how long they are effective after their expiration date. They did this because they were disposing of millions of dollars worth of medications EVERY YEAR after the medication's expiration date. The testing was done over approximately 15 years. They found that the drugs were still 80 to 90%' effective after all those years if they were well sealed and not exposed to moisture. This does not apply to anti-biotics and liquid medication. I took a Provigil that was 12 years old and it was just as effective as the time that I picked it up from the pharmacy.

If its stored correctly, and the container was closed tightly, it may be good after a year, but the drug company won't tell you that. Their tests are on drugs that they could control the way they were stored, so won't risk saying a longer time is ok. If you try one and it helps, then its probably ok.

Hello kim108. Most all perscriptions are considered to be out of date a year after having been filled. Regards pledge