I remember from my pharmacology course my teacher told us that the ONLY compound you should never take once it has expired is acetaminophen/paracetamol since it breaks down to NAPQI all by itself over time. Everything else, however, is not toxic. It just simply loses potency over time.
Of course as a physician prescribing medication you would never recommend taking expired medication since, as mentioned in TFA, the manufacturer does not guarantee potency. Therefore you cannot know if the therapeutic dose can be reached in your patient. Since there's a risk of patients not being treated with expired meds, you always recommend they take non expired medication.