CONCURRENT ADMINISTRATION WITH MAOIS THE FATAL REACTION HAVE BEEN REPORTED. AMIODARONE, FLUOXETINE, HALOPERIDOL, PAROXETINE, PROPAFENONE, QUINIDINE, AND THIORIDAZINE & RITONAVIR CAN INCREASE SERUM CONCENTRATION OF DEXTROMETHORPHAN. PROMETHAZINE HCL AND DEXTROMETHORPHAN HYDROBROMIDE SYRUP IS CONTRAINDICATED FOR USE IN PEDIATRIC PATIENTS LESS THAN TWO YEARS OF AGE, CAN CAUSE RESPIRATORY DEPRESSION & DEATH.