Mucinex Fast Max: Severe Congestion and Cough Liquid (dextromethorphan, guaifenesin, phenylephrine*) Cough, chest and nasal congestion; for use in adults and children 12 years and older. Mucinex Children’s: Multi-Symptom Cold Liquid Very Berry (dextromethorphan, guaifenesin, phenylephrine*) Cough, ...