Best medicine for my 4 year old??

Courtney

My poor daughter is 4 and she has a very stubborn cough. She has been waking up multiple times a night from coughing. Is there any cough and cold that really works for that age? Zarbees and Hylands did nothing. We have been putting Vicks rub on her feet and chest, elevating her head and having her breath in steam before bed. Any suggestions? Thanks in advance!