Sudafed is one of many over-the-counter decongestants that works to relive sinus pressure, states WebMD. It works by reducing the swelling in the nasal passages, easing the pressure.
Sudafed works to relieve pressure in the frontal, ethmoid, maxillary and sphenoid sinuses, states the Sudafed website. To help make Sudafed more effective at relieving pressure and congestion, it is a good idea to place a cold compress or ice pack on the affected area. Taking a pain reliever or gently massaging the neck also helps relieve pain associated with sinus pressure. If a person takes Sudafed and still has sinus pressure or nasal congestion after seven days, he must see a doctor to see if an underlying medical condition is the source of the problem, states WebMD.