Most sites have extensive information about the benefits and risks of a prescribed medication. If they don't they should. When a doctor issues refills, a patient deals directly with the pharmacist. Many sites online do follow up questionnaires on refills to ensure there has been no side effects or the patient is not taking some new medication. Responsible sites offer more follow ups on their patients than the average GP does.
Most sites carefully explain the contraindications with the product they are selling.
If they don't they should be required to. Of course that is run by the Federal Government, so we assume there will be a politically correct reason why such a deadly combination of medications are dispensed. Perhaps it was just an inappropriate mistake. The Industry does not object to being regulated, but we do object to regulations attempted to be imposed making crimes and criminals out of people in circumstances where the regulations presently in place were never intended to apply. We object to raids by authorities with manufactured probable cause and sealed affidavits.