my morphine sulfate says to discard 3 months after opening, does it expire after this date or lose its potency or something?

idk if it's just a pharma precaution or some shit like I've gotten high off expired codeine phosphate before but I'm wondering if it's any different because there is sucrose and corn syrup in it.

I'm guessing the active ingredient will still get me high but I'm worried the liquid will expire and make me ill.