What medication can you take for a persistent cough?

Depending on how persistent it is, it is different for some people. AT points in time, I will be in class doing my work and all the sudden start couching but can't stop. If that is what happens to you, then I can help, hopefully. SO, what I do is stand up first and ask to go to the water fountain. Don't try to hold in your cough or anything because you won't be able to breath. So, take your time going to the fountain and stand straight. Don't slouch. Then, I go back to class and go on with my work. Usually, it comes back, so what I do is just stand up from my desk straight, I don't even go back out to get water. Just stand up from your desk and breath slowly, in and out.