Decongestants may help shrink swollen tissues in the nose, sinuses, throat, and the space behind the eardrum (middle ear). This may relieve pressure and pain.
Decongestants can be taken by mouth (oral) or used as nose drops or sprays. Oral decongestants are probably more effective and provide longer relief, but they cause more side effects. There are only two nonprescription decongestants that you can take as a pill: pseudoephedrine (such as, Contac Non-Drowsy, Sudafed) and phenylephrine (such as Sudafed PE). In some states, any medicine that contains pseudoephedrine is kept behind the pharmacist's counter so you will need to ask the pharmacist for it. In other states, you have to have a prescription from your doctor to buy medicine containing pseudoephedrine.
Sprays and drops provide rapid but temporary relief. Neo-Synephrine is an effective nasal spray. Sprays and drops are less likely to interact with other medicines, which may be a problem with oral decongestants.
Decongestant precautions
WebMD Medical Reference from Healthwise