I would imagine if you were in the study you get paid for the night spent. The real question is if the drug had adverse effects on health including labs do you get the complete payment since you have harmed. You certainly would be paid for safety return visits. These questions are best asked before you do a study so you know how to proceed in the eventuality the scenario happens.
Where dropped because of illicit drug use or not following protocol? Other than that there is normally an alt or overnite pay if you are complaint otherwise. You might want to pick up the issue with the clinic if its still unresolved the irb board on your consent might be your next best option!