There are several different types of decongestants available in several forms, including:

• Eye drops
• Tablet
• Capsule
• Liquid
• Nasal spray

Most nasal spray decongestants work very quickly (in about 10 minutes) and can help to reduce nasal congestion for up to 12 hours. Nasal sprays also affect only the areas of the nose and sinuses, limiting the number and severity of side effects (which may include a stinging or burning sensation within the nose or nosebleeds).

Oral decongestants (tablets, capsules or liquids) begin to work in about 30 minutes and some can reduce nasal congestion for up to 24 hours. Oral forms of the medication cause blood vessels to constrict throughout the body, which can help reduce effectiveness and are more likely to cause adverse side effects (such as increased blood pressure or difficulty urinating).

Some medications combine decongestants and antihistamines, which delivers a two-pronged approach to relieving allergy symptoms. In addition to reducing nasal congestion, sneezing and other allergy symptoms, these combinations also block the histamines that the immune system uses to produce allergy symptoms.

Most decongestants are available over-the-counter (OTC) and though there are several brands available, all contain similar medicine that works in the same manner. 

Decongestants in common use include: 

It is very important not to exceed the dose of any medication, including OTC drugs. Follow all directions on the package and contact a physician if there are any questions about the medication or its effects. Depending on local laws, OTC medications with ephedrine and pseudoephedrine may be kept behind the counter – rather than on store shelves – because of widespread abuse of these drugs. It may be necessary to ask a store clerk or pharmacist for assistance when purchasing these medications. Some stores may also require the customer to be 18 years of age or older.