 Dextromethorphan phenylephrine thonzylamine and Trifed C Drug Interactions - Drugs.comDrug interactions between dextromethorphan phenylephrine thonzylamine and Trifed CApplies to: Trifed C codeine pseudoephedrine triprolidine and dextromethorphan phenylephrine thonzylamineApplies to: dextromethorphan phenylephrine thonzylamine and Trifed C codeine pseudoephedrine triprolidine 