My 4 year old has a bad cold and iv tried everything i can,even prescription meds from her last cold. i have equate multisyomtom cold stuff like theraflu. can i give her just a little bit for her cough so she can sleep without being woken up from it?

You are expecting too much from medications; the best thing to help her is to give lots of warm liquid like in soup, tea, chocolate drinks with milk when going to bed. It helps to improve the ease of coughing out the mucus and the germs. It may help her immunity. The cough syrup are not as good as you think; with side effects especially when it is better to cough up the mucus.