I used to go nuts making sure my youngest kids had nothing in their backpacks that could be construed as weapons, or controlled substances. Cough drops can fall under that category, if the teacher has his/her head far enough up their ass.
Tylenol or throat drops require an doctor's prescription AND a faxed form letter detailing how/when it is to be administered.
I just give my son the tylenol and tell him to not to let anyone see him take it and if the drug dogs come to school to swollow it immediately.