Is there a drug or poison that would give someone chest pains, or other symptoms that would make them think they're having a heart attack? Or any other sudden medical condition that would make people call an ambulance, like a stroke or something?
Yes, of course, strokes are sudden and make people call an ambulance. Do you actually need a poison/drug or just need someone to call an ambulance?
I need a poison/drug that brings the symptoms on. The idea is to fool the victim into thinking that he's having a heart attack, when in fact there's nothing wrong with him.
Hyperkalemia would produce a real heart attack. Playing with potassium levels is dangerous, to much and they really have a heart attack. Any medicine that makes a person dizzy or light headed, these are signs of a stroke. If you can get a smear of nitropaste on the person, they will get a massive headache. This combo could be enough to, with encouragement, to call an ambulance. Even better slip the dizzy making med to the person, and have the plotter offer concern, and suggest a stroke, and tell the target that another symptom is a massive headache, then slip the nitro. The amateur diagnosis is reinforced.