Topical Antifungal & Expiration?

I just found ciclopirox gel and solution that I had been prescribed about 4 years ago for nail fungus. The problem resolved, and now I'm starting to see early signs of the nail fungus reappearing. I just found the left over meds I have, and I know they're well past their expiration date, but I was wondering from a pharmacological standpoint if they've completely lost efficacy, and if it would be safe to even try using it. I plan on calling my doctor this week to refill the script, but in the meantime, I was just curious to know if it would be even worth using it. Thanks!