Synasma doe not cause this type of pain (I would suggest that you use generic drug name instead of a brand name as an ethics). Although, theophylline
group of medicines are known to cause neurological side effects including convulsions. So they should be used with caution.
Remember a simple rule for asthma: Patient should be only on preventers (accuhaler in your case) regularly and should need very occassional salbutamol
as a reliever. If salbutamol is needed on more than 3 instances in a week, you need to step up preventive treatment.
Infection needs antibiotics and not doxophylline
! Not all asthma exacerbations are due to infection. In fact very few are.