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 congestion when you have:
a common cold
hay fever, or other allergic reactions, such as to dust mites
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
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 so they block your nasal airway, making it difficult for you to breathe through your nose.
Decongestants reduce 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.
Things to consider when using decongestants
Decongestants are not usually recommended for children under twelve years of age, for woman who are breastfeeding and for people with certain health conditions such as high blood pressure.
It is is not recommended to use decongestants for more than seven days as they can cause your nose to become more blocked once you stop taking them (rebound congestion).
If your symptoms fail to improve after this time you should contact your GP.
In most cases where side effects occur after taking decongestants they tend to be mild, such as:
More serious side effects have been reported, such as hallucinations (seeing and hearing things that are not real) and a severe allergic reaction (anaphylaxis), but these are rare.
It is now commonplace for decongestants to be sold as part of an ‘all-in-one’ cold, flu or hay fever remedy, where the decongestants medication is also combined with painkillers, such as ibuprofen or paracetamol or with antihistamines (used to treat allergies).
It is important to carefully read the patient information leaflet that comes with your medication as it could be dangerous to take one of these ‘all-in-one’ remedies and then go on to take extra ibuprofen, paracetamol or antihistamines.
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.