Degraded tetracycline has been documented to be dangerous in those who are suffering from renal failure.
There's also the possibility that a person may be suffering from a new undiagnosed condition, which hadn't yet onset when they were initially prescribed the drug. In this case you could think of it less as an expiration for the drug, and more of a suggestion to seek additional medical guidance on continuing after a certain date.
There's also the remote possibility that a new drug is developed which could potentially become dangerous when expired. The general population would have to unlearn little morsels of knowledge such as this, in the meantime people could be harmed.
Edge cases like this are enough in my opinion to warrant not spreading blanket advice like this, even if it's nearly always true. Erring on the side of caution is the best approach with medical affairs, even if it costs a bit extra monetarily. Giving patients potentially dangerous advice so they can save money is ethically questionable at best.
There's also the possibility that a person may be suffering from a new undiagnosed condition, which hadn't yet onset when they were initially prescribed the drug. In this case you could think of it less as an expiration for the drug, and more of a suggestion to seek additional medical guidance on continuing after a certain date.
There's also the remote possibility that a new drug is developed which could potentially become dangerous when expired. The general population would have to unlearn little morsels of knowledge such as this, in the meantime people could be harmed.
Edge cases like this are enough in my opinion to warrant not spreading blanket advice like this, even if it's nearly always true. Erring on the side of caution is the best approach with medical affairs, even if it costs a bit extra monetarily. Giving patients potentially dangerous advice so they can save money is ethically questionable at best.