Mucinex Sinus-Max Severe Nasal Congestion Relief Sinus & Allergy is an over-the-counter medicine that provides targeted nasal congestion relief due to allergies. It's non-drowsy, fast-acting and lasts up to 12 hours, through the day or night. Mucinex Sinus-Max Severe Nasal Congestion Relief helps relieve nasal congestion, sinus congestion and sinus pressure.