Drugs that are used to reduce swelling of the membranes lining the nose and sinuses

Common drugs

  • Ephedrine

  • Oxymetazoline

  • Phenylephrine

  • Pseudoephedrine

  • Xylometazoline

Decongestants act to relieve congestion in the nose and sinuses. A blocked nose or sinuses (see Sinusitis) may be caused by a viral infection, such as the common cold, or by an allergic condition, such as hay fever (see Allergic rhinitis).

Infections and allergic reactions can cause inflammation of the delicate lining of the nose or sinuses. The blood vessels in the lining enlarge, and increased volumes of fluid pass into the mucous membranes, which swell and produce excessive amounts of mucus. Decongestants act directly on the blood vessels to constrict them and reduce the swelling and mucus secretion.

Decongestants are available as sprays or drops that are used in the nose or as oral pills or capsules. Some cold and flu remedies that are available over the counter also contain a small amount of decongestant. You can spray or insert decongestant drops directly into your nose to provide rapid relief. When taken orally, decongestants work more slowly, but the effects last longer.

Decongestant sprays or drops should be used in moderation and for no longer than a week. After that time, they may lose their capacity to constrict blood vessels. When the last effective dose wears off, the blood vessels widen again, and congestion may become worse.

Used sparingly, decongestant sprays or drops have few side effects. If you have heart disease or high blood pressure, you should check with your doctor or pharmacist before using decongestants because they sometimes cause a rapid, irregular heartbeat and raise blood pressure. Decongestants must be avoided by people taking MAOIs (monoamine oxidase inhibitors, a group of antidepressant drugs) because the drugs may interact to cause a dangerous rise in blood pressure. Decongestants may also cause a slight tremor in the hands.


Avoid using decongestants for longer than a week because the drugs may become ineffective or worsen your condition.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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