Unsafe: No. Loss of potency: Yes (to a degree)!

In the original factory sealed bottles that your pharmacy receives, most medications are touted to only be good for 3 years. Once those are opened and they are placed in a bottle that exposed them to heat and light, they're subject to degrade faster and will lose potency.

On the contrary however, something to keep in mind is that according to Harvard University’s Medical Center, “Most of what is known about drug expiration dates comes from a study conducted by the Food and Drug Administration at the request of the military. With a large and expensive stockpile of drugs, the military faced tossing out and replacing its drugs every few years. What they found from their study is that 90% of more than 100 drugs, both prescription and over-the-counter, were perfectly good to use even 15 years after the expiration date. So, the expiration date doesn't really indicate a point at which the medication is no longer effective or has become unsafe to use. While it's true that the effectiveness of a drug may decrease over time, much of the original potency still remains even a decade after the expiration date.”

Ref: health.harvard.edu/staying-healthy/drug-expiration-dates-do-they-mean-anything

Hope this info helps!