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Decongestant drugs

Page last reviewed: 13/07/2011

Decongestants are a type of medicine that can provide short-term relief for a blocked nose (nasal congestion). They can be taken to ease the symptoms of mild conditions such as the common cold, hay fever or nasal allergies.

Many decongestants can be bought over the counter in pharmacies without a prescription. They are available as tablets or a nasal spray.

How decongestants work

Decongestants reduce the swelling of the blood vessels inside your nose. This helps to open up your nasal airway, making breathing easier.

However, although decongestants can help you to breathe more easily, they cannot cure the underlying cause of your blocked nose, such as a cold or allergy.

Also, decongestants are effective in clearing nasal congestion over short periods of time. It is unlikely they will work for more than five to seven days, and they can even cause your nose to become more blocked once you stop taking them (rebound congestion).


Some of the most common decongestants are:

  • pseudoephedrine (Sudafed)
  • Oxymetazoline (Vicks Sinex)
  • Xylometazoline (Otrivine)

Decongestant medicines are available as tablets or a nasal spray

Why is my nose blocked?

The inside of your nose is lined with many tiny blood vessels. When these blood vessels are irritated by something, such as an infection or an allergy, more blood flows to them as part of your body's immune response.

This extra blood makes your blood vessels swell up so they block your nasal airway, making it difficult for you to breathe through your nose.

Page last reviewed: 13/07/2011

Most people can use decongestant medicines, although they may not be suitable for everyone.

Babies and children

Decongestants are not recommended for children who are under six years of age.

If your child has a stuffy nose, breathing in steam with added essential oils, such as eucalyptus or rosemary, may help to relieve it.

For babies, you may find that placing a few drops of saline (salt water) just inside their nose, before they feed, will help to relieve a blocked nose. Saline drops are available from pharmacies.

Pregnancy and breastfeeding

If you are pregnant or breastfeeding, it is best not to take any kind of medicine. However, if you have a blocked nose and feel you cannot cope with your symptoms, some decongestants are considered safe for short-term use.

You should not take decongestants containing pseudoephedrine, phenylephrine or xylometazoline during the early stages of your pregnancy.

Ask your GP or midwife for advice before taking any medication.

When to avoid decongestants

It may not be safe for you to take decongestants if you have certain health conditions. Talk to your GP before using a decongestant if you:

  • have diabetes
  • have high blood pressure (hypertension)
  • are being treated for an overactive thyroid gland (hyperthyroidism)
  • have an enlarged prostate gland
  • have liver damage
  • have kidney damage
  • have heart disease
  • are taking a monoamine oxidase inhibitor (a type of antidepressant medication)

Page last reviewed: 13/07/2011

Decongestant medicines do not often cause side effects, and any side effects you may have are likely to be mild.

Possible side effects of decongestant nasal sprays may include:

  • irritation to the lining of your nose
  • headaches
  • nausea (feeling sick)

In some cases, decongestants containing a medicine called pseudoephedrine can increase your heart rate, which may make you feel restless and affect your sleeping.

Some decongestants also contain other medicines, such as antihistamines, to reduce allergic reactions. Antihistamines can make you feel drowsy, so if they are included in your decongestant you should always read the instructions before driving or operating machinery.

Page last reviewed: 13/07/2011

Decongestant medicines can be taken in two ways:

  • as tablets
  • as a nasal spray

Decongestant tablets may take a little longer to work, but their effect can last longer than nasal sprays.

You should not use decongestants for more than five to seven days at a time. This is because they can only provide short-term relief for a blocked nose, and using them for any longer can make your symptoms worse.

Rhinitis medicamentosa

Rhinitis medicamentosa is a type of non-allergic rhinitis caused by the overuse of nasal decongestants.

Nasal decongestants reduce the swelling of the blood vessels inside your nose. However, if decongestant sprays are used for more than five to seven days at a time, they can cause your nasal lining to swell up again, even when the cold or allergy that originally caused the problem has passed. If you use more decongestants in an attempt to reduce the swelling, it is likely to make the problem worse. This is known as 'rebound congestion'.

Some people find they get locked into a cycle of overuse and dependence on nasal decongestants, much like a drug addiction.

Always follow the instructions on the patient information leaflet that comes with your medicine to make sure you do not take too much. Alternatively, ask your GP or pharmacist if you are unsure about the correct dosage.


Congestion is an excess of fluid in part of the body, often causing a blockage.
Clinical trials
Clinical trials are research studies to test new types of treatments, preventions and diagnoses on patients.
Dose is a measured quantity of a medicine to be taken at any one time, such as a specified amount of medication.

Page last reviewed: 13/07/2011

Some decongestants also contain painkillers, such as paracetamol or ibuprofen. If you are already taking a painkiller for other symptoms, such as headaches or a fever, make sure you do not exceed the maximum dose when also taking a decongestant.

You should not take decongestants if you are taking a type of antidepressant called a monoamine oxidase inhibitor, as this can cause a dangerous rise in blood pressure.

Before starting to take any decongestant, make sure you check the patient information leaflets that come with your medicines, or see your GP or pharmacist for advice.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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