Drowsy since 2 days. At that time?

My son is 2 years 4 months old...he has got cough..cold and fever from past 5 days... the following medicines were given For fever - Babygesic For cold - Sinarest A F For cough - Mucolite he was fine initial 4 days..even though fever was there..he was active and was playing asusual...but was not sleeping properly inspite of medicines,as cold and cough were more when he sleeps.. Since yesterday( sunday) he is drowsy...and not willing to wake up..even if he wakes up,he is eating and again sleeping..he is not staying awake.. also his breathe is fast..more than 50 breathes per minute We are now in UK..we have taken him to hospital..they have examined and said fast breathe and drowsiness is all because of viral infection. But my son is an active kid.. My question is..Is all the sinarest and Mucolite which he had 2 days back making him drowsier now ,as he dint sleep properly at that time ??