Does Bronchodilator Doxofylline Cause Any Side Effects?

Dear Doc, my 4 months old son has been consistently coughing for 10 days now. His doctor conducted a skin test to find out if he's TB positive, and while waiting for the results, she prescribed a bronchodilator Doxofylline (Ansimar) 100mg/5ml syrup for my baby. Based on my research, there are no recommended cough syrup for children below 6 months old. Since she is a pediatrician and pulmunary expert at that, I wish to seek other opinions whether it is safe to give my baby the medicine that was prescribed. Thank you in advance.