I know of an incident in which an aircrew member found himself in the company of an individual suffering acute pain. The source of the pain was clear to see and therefore genuine. The ‘good Samaritan’ opened his aircrew first aid kit and donated a painkiller tablet from it to the ‘patient’.
Shortly afterwards the patient had hallucinations of being chased by alligators and snakes replacing the pain. A GP who arrived on scene suspected a deliberate overdose which was far from the truth. Side effects which were never warned about despite every crew member being in possession of said drugs. I believe that the contents of the aircrew first aid kit have since changed but do not know to this day if the painkillers in this story remain in the kit.