Hi Sanjay Kumar,
Thank you for your query on Healthcare Magic.
Phena-Kid syrup contains promethazine
Promethazine causes drowsiness
, sedation, and hypotension
Usually it is indicated in nausea, vomitings, allergy, and in motion sickness
Usually it is safer in children above the age of 2 years, and it should be used with the prescription of a Pediatrician
I advise you to stop the use of this syrup in your five months old child.
For cough you can use cough drops containing mucolytic such as ambroxol in prescribed dosage as advised by your Pediatrician.
Therefore I advise you to consult the Pediatrician, get your child examined, and for medication.
Hope I have answered your query.