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  Oct 09, 2018

Common Decongestants

Decongestants are drugs used to relieve the nasal congestion that may occur when a person suffers form a cold, flu, hay fever or sinusitis.

These drugs are available in the form of sprays or nasal drops (topical decongestants) or as tablets or capsules that can be taken orally. The decongestant might also be combined with a pain killer such as paracetamol. Other forms of nasal decongestants are steam inhalation and saline nasal drops. Steam inhalation can provide temporary relief from the congestion and saline drops are often used to treat babies with a blocked nose.

Congestion is caused by swelling of the blood vessels inside the nose in response to irritation in cases of infection or allergy. These swollen vessels block the nasal airways and obstruct nasal inhalation. In addition, glands in the affected areas start to produce mucus to trap pathogens. Together, the swollen vessels and excess mucus production can block the nose and cause nasal stuffiness.

Decongestants work by acting on adrenergic receptors in the nose which constricts the blood vessels, as well as reducing inflammation and mucus formation in these areas.

Some of the agents commonly used in decongestants include pseudoephedrine, phenylephrine, levomethamphetamine, propylhexedrine, synephrine, tetrahydrozoline, naphazoline, oxymetazoline and xylometazoline. However, the active ingredient in a decongestant is usually either pseudoephedrine or phenylephrine and these are described in more detail below.


This agent is used to relieve the symptoms of congestion, but cannot treat the cause of the problem or accelerate recovery. Pseudoephedrine can be taken as regular tablet or as a long- long-acting agent that is released over a 12- or 24- hour period (extended release). The drug can also be taken in liquid form. The liquid or tablet is taken every 4 to 6 hours, while the 12-hour extended release tablet is taken every 12 hours and the 24- hour extended release tablet is taken once a day.

Medications containing pseudoephedrine that are not prescribed can lead to serious adverse side effects or even death in young children. These nonprescribed products should not be given to children aged under 4 years, and when given to children aged 4 to 11 years, the directions should be followed very carefully to ensure that the product is suitable for the child and that they receive the correct dose for their age. The extended release forms of this medication should not be given to any child aged under 12 years.


  • People taking this drug should check the exact ingredients of the product and inform their doctor or pharmacist if they are allergic to any of them. The doctor or pharmacist should also be informed of any other medications the person is allergic to.
  • The doctor or pharmacist should be informed of any other medications the person is taking including any herbal or nutritional supplements, antihypertensive medications or drugs to treat asthma, for example.
  • Pseudoephedrine should not be taken if a patient is already taking a monoamine oxidase inhibitor such as selegiline, tranylcypromine or phenelzine.
  • People planning to take this medication should inform their doctor if they have glaucoma, high blood pressure, diabetes, thyroid disease, heart disease, or difficulty urinating. Women should also inform their doctor if they are pregnant, breast feeding or planning to become pregnant.
  • A doctor should be informed if a patient is due to have surgery, including dental surgery.
  • A large intake of caffeine can increase the adverse side effects of this medication.
  • If a dose of pseudoephedrine is missed, the missed dose should be taken as soon as the person realises. If it is almost time for the next dose, however, the missed dose should be skipped and the next dose taken instead.

Side effects

Pseudoephedrine can cause vomiting, headache, nausea, vomiting and restlessness. More severe effects include dizziness, breathing difficulty, insomnia, dizziness, abdominal pain and a fast or irregular heartbeat.


Phenylephrine is used in the treatment of sinus/nasal congestion or Eustachian tube congestion. The Eustachian tubes drain fluid from the inner ear.

The medication should be used exactly as the product instructions advise and not in any larger or smaller doses than recommended. The medication should not be given to children aged under 4 years and the instructions should be carefully checked before giving the drug to any child because it can cause serious side effects and even death.

The drug can be swallowed in liquid form or as a chewable tablet and products containing this agent should be stored at room temperature and not exposed to moisture or heat.


This medication should not be taken if patients are already being treated with a monoamine oxidase inhibitor.

People planning to take this drug should tell their doctor if they are allergic to decongestants or if they have diabetes, a thyroid disorder, high blood pressure or heart disease.

Phenylephrine is classed by the Food and Drug Administration as pregnancy category C. The effects on an unborn baby in mothers who take the drug is not known and women should not take this medication without the supervision of their doctor. It is known that phenylephrine can pass into the breast milk and cause harm to babies that are nursing. The medication should therefore not be used by mothers who are breastfeeding.

Patients should inform their doctor if they are due to undergo surgery

If a dose of phenylephrine is missed, the next dose should be taken as soon as possible, unless it is almost time for the next dose, in which case the missed dose should be skipped.

Side effects

Common side effects of using this medication include insomnia, skin rash, restlessness and loss of appetite. More severe side effects include a fast or irregular heartbeat, dizziness, anxiety, weakness, body aches, tendency to bruise or bleed easily, chest pain, difficulty breathing, headache and blurred vision.