First off, a prescription that you had filled about a year ago is still likely to be substantially ahead of its expiry date. But those expiry dates are nothing but a marketing strategy, anyway. If they can get people to throw away drugs, and you need some more, you have to get a new supply. There is no scientific evidence that drugs expire, with only limited exceptions. Properly stored, i.e. room temperature, limited humidity, in the dark, drugs last indefinitely. Except for some antimicrobials. Aspirin is another exception. If it smells of vinegar, it is autocatalyzing its own destruction. It'll still work, but it is more prone to causing stomach problems.

The U.S. military has massive stockpiles of medications, some going back to the 2nd World War. They wanted to avoid the expense of replacing "expired" meds, so they tested them. They found no loss of efficacy, except within the class of antimicrobials. But if you're prescribed one of those, you're supposed to use it up completely, anyway, so the issue is truly moot.

Lar