how long does nyquil stay in your system?
Dextromethorphan: This ingredient is included in all NyQuil formulas except âNyQuil Sinus.â Dextromethorphan, also known as âDXM,â has an elimination half-life of 3 to 6 hours, but may narrowed within the range of 2 to 4 hours among those with normative metabolism.