My baby is just about turning 6 months old.he has come up with a mild dry cough..I initially felt it was due to him over straning his voice while screaming...but now he coughs more regularly.he was checked up n said no chest congession just a change in weather may have caused it..dinar eat drops were prescribed .bive given him three doses 6 hrs apart but noticed he is sleeping too much...is this medication ok??