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Allergies > Decongestants

Decongestants

Decongestants can treat one of the common symptoms of allergic rhinitis:

- a blocked nose

How do Decongestants work?

A blocked nose is the result of increased blood flow to the lining of the nose. This causes swelling and reduces the space through which air can pass. A runny nose also reduces air flow through the nose.

Decongestants cause blood vessels to become narrow by mimicking a chemical found in the body (noreprinephrine) that naturally causes blood vessels to constrict.

The narrowing of blood vessels reduces the volume of blood reaching the nose lining. This reduces any swelling within the nose and provides a larger passage for air to flow through.

Read our article about the basics of allergy testing

Which Decongestants Should i take?

Decongestants can be taken orally as tablets or liquid, or can be applied as nasal sprays or drops. Nasal sprays and drops are more effective as they are applied directly to the affected area. The following table gives some examples of decongestants available in the UK, US, and Canada for the treatment of allergic rhinitis. Only brand name drugs are listed, but generic versions may also be available.

Where can i get Decongestants?

Many decongestants can be bought from your local pharmacy, although some will need a prescription from your doctor. Your doctor will be able to advise which one would be best for you.

Are Decongestants Safe?

Decongestants taken as a tablet or liquid may cause nervousness, irritability, a high pulse rate, palpitations (irregular heart beat), headache, and insomnia (inability to sleep). People at risk from high blood pressure should not use decongestants.

There is less risk of the above side effects when decongestants are taken using a nasal spray or drops. However, these should not be used for more than 10 days continuously as long-term use may lead to drug tolerance (when the drug no longer works), further nasal swelling, or may lead to rhinitis symptoms caused by the drug itself (rhinitis medicamentosa).

If your child is less than 1 year old, you should consult your doctor before giving them decongestants.

What Drugs can i take at the same time?

In some cases, a combination of different drugs may be useful in treating allergic rhinitis. Your doctor can advise you on whether you may benefit from this.

Antihistamines and decongestants

Antihistamines are good at treating sneezing, an itchy nose, and a runny nose, but they are less good at treating a blocked nose. They may therefore be used at the same time as oral decongestants, which are effective at relieving a blocked nose.

Combinations of antihistamines and decongestants can counteract all the symptoms of allergic rhinitis on a short-term basis. Click here for some treatments containing both antihistamines and decongestants.

Topical corticosteroids and antihistamines

Topical corticosteroids and antihistamines are both very good at treating a runny nose, sneezing, and an itchy nose, and topical corticosteroids are also good at treating a blocked nose. If you have severe allergic rhinitis, your doctor may advise that you use both topical corticosteroids and antihistamines to control your symptoms.

References

Gentile DA, Friday GA, Skoner DP. Management of allergic rhinitis. Antihistamines and decongestants. Immunol Allergy Clin North Am 2000;20:355–368.

Dykewicz MS, Fineman S, Skoner DP, et al. Diagnosis and management of rhinitis: complete guidelines of the Joint Task Force on Practice Parameters in Allergy, Asthma and Immunology. Ann Allergy Asthma Immunol 1998;81:478–518.

van Cauwenberge P, Bachert C, Passalacqua G, et al. Consensus statement on the treatment of allergic rhinitis. European Academy of Allergology and Clinical Immunology. Allergy 2000;55:116–134.