Are benzos (xanax, ativan, (lorazepam) etc) still as effective 2 years after the rx was filled? it says it has "expired" but chemically i cannot see how or why

Unclear: Most medications tend to deteriorate over time simply because they are to some degree chemically unstable. The longer the time, the more they have deteriorated. However, this is a generalization, and it varies to what degree it is true for any specific medication. Two years is long enough such that one cannot verify a medication's potency. Most likely at least some potency has been lost.

Call your Pharmacist: The direct answer is to call your pharmacist and ask about the expire date and the loss of effectiveness of the medication. Medications expire just like other products we buy with expiration dates. Are you likely to throw out milk that has expired? You may not because it still taste fine. With medication dates it is the last guaranteed date that the medicine meets standards for effectiveness.