An oral decongestant
Pseudoephedrine
An oral decongestant that unblocks a stuffy nose; raises blood pressure and heart rate, so it is used with caution and is pharmacy-controlled.
What is Pseudoephedrine?
Pseudoephedrine is an oral decongestant taken to relieve a blocked or stuffy nose, for example with colds, sinus congestion or hay fever. It works by narrowing the swollen blood vessels in the nose to improve airflow.
Education and reference only. This is a plain-language guide to Pseudoephedrine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Pseudoephedrine is an oral decongestant, taken as a tablet or liquid to relieve a blocked or stuffy nose — for example with colds, sinus congestion or hay fever. Unlike a decongestant nasal spray, which acts locally, pseudoephedrine works throughout the body, which makes it effective but also means it can raise blood pressure and heart rate. For that reason, and because it can be misused, its sale through pharmacies is controlled. It is best known under the brand Sudafed, and also appears in many combination cold-and-flu remedies.
How it works
A blocked nose is caused by swollen, engorged blood vessels in the lining of the nose. Pseudoephedrine stimulates the same receptors that adrenaline acts on, causing these blood vessels to tighten and shrink, which reduces the swelling and opens up the nasal passages so you can breathe more freely. Because those same receptors are found throughout the body, pseudoephedrine can also tighten blood vessels elsewhere and stimulate the heart — which is the source of its main cautions.
Company & origin
Originated / developed by: No single originator (natural alkaloid; popularised by Burroughs Wellcome as Sudafed).
Pseudoephedrine is a naturally occurring alkaloid first isolated from Ephedra plants by German chemists Ladenburg and Oelschlager in 1889. It was later developed as the decongestant Sudafed, long associated with Burroughs Wellcome (now part of GSK).
What it treats
Conditions Pseudoephedrine is used for
Practical use
How to take Pseudoephedrine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it as directed and avoid taking it late in the day, as it can keep you awake.
- Use it only for a short time to relieve congestion, not on an ongoing basis.
- Be aware it can raise blood pressure and quicken the heartbeat, so use caution if you have heart problems or high blood pressure.
- Avoid other decongestant remedies at the same time, as the effects can add up.
- Speak to a pharmacist if symptoms last more than a few days or you take other medicines.
Weighing it up
Advantages & disadvantages of Pseudoephedrine
Advantages
- Effectively relieves a blocked nose and sinus congestion.
- Works throughout the body, helping congestion that nasal sprays may not reach.
- Available without prescription for short-term use.
- Acts relatively quickly to ease stuffiness.
Disadvantages
- Can raise blood pressure and speed up the heart, so it is not suitable for everyone.
- May cause restlessness, anxiety or difficulty sleeping, especially if taken late.
- Not recommended for people with certain heart, blood-pressure, thyroid or prostate conditions.
- Can interact with some other medicines, including certain antidepressants.
- Intended only for short-term use to relieve symptoms.
Practical use
Good to know
It is taken for short-term relief of congestion, not for ongoing daily use. Because it can raise blood pressure and heart rate and can stimulate the system, it is used with caution — and often avoided — in people with high blood pressure, heart disease, an overactive thyroid or certain other conditions; a pharmacist will ask about these before selling it. Taking it later in the day can disturb sleep, so a daytime dose is usually better. It must not be taken with, or close to, a type of antidepressant called a MAOI, as the combination can cause a dangerous surge in blood pressure. Its pharmacy sale is restricted to limit misuse.
Who should not take it / use with caution
- People taking a monoamine-oxidase-inhibitor (MAOI) antidepressant, now or recently — the combination can cause a dangerous rise in blood pressure.
- People with high blood pressure that is not well controlled, significant heart disease, or an overactive thyroid.
- Used with caution in diabetes, glaucoma, an enlarged prostate with difficulty passing urine, and in pregnancy.
Monitoring
- Usually none for short-term use
- Blood pressure awareness in people with hypertension or heart disease
- Review if congestion persists
Side effects
- A faster heartbeat, palpitations, or a rise in blood pressure.
- Restlessness, anxiety, and difficulty sleeping — especially if taken later in the day.
- Dry mouth, headache, or difficulty passing urine; rarely, more serious effects on the heart or, with overuse, on the circulation.
Key interactions
- It must not be combined with MAOI antidepressants (or used within a couple of weeks of stopping one) — a dangerous blood-pressure surge can result.
- It can reduce the effect of blood-pressure medicines and add to the stimulant effect of other decongestants or some other medicines.
- Tell your pharmacist about your other medicines, as many cold-and-flu products already contain a decongestant.
Available as: Tablets and liquids, on their own or combined with painkillers and other ingredients in cold-and-flu remedies; sold under pharmacy supervision.
Answers
Pseudoephedrine: frequently asked questions
Can I take pseudoephedrine if I have high blood pressure?
You should be cautious. Pseudoephedrine can raise blood pressure and heart rate, so it is often avoided in people with high blood pressure or heart disease. Always tell the pharmacist about your blood pressure before buying it — they may recommend a decongestant nasal spray or a different approach instead.
Why is pseudoephedrine kept behind the pharmacy counter?
Its sale is controlled partly to limit misuse and partly so a pharmacist can check it is suitable for you — for example asking about blood pressure, heart problems, thyroid issues and other medicines. This is why you usually have to ask for it rather than picking it off the shelf.
Why does pseudoephedrine keep me awake?
It is a stimulant as well as a decongestant, so it can cause restlessness and make it harder to sleep, particularly if taken in the evening. Taking it earlier in the day, and not late at night, helps avoid this.
Can I take pseudoephedrine with my antidepressant?
Not with one type — a MAOI (monoamine-oxidase inhibitor). Combining pseudoephedrine with a MAOI, or taking it within a couple of weeks of stopping one, can cause a dangerous surge in blood pressure. Always tell the pharmacist about any antidepressant you take before buying it.
What is the difference between pseudoephedrine and Sudafed?
They are the same medicine — pseudoephedrine is the generic (active-ingredient) name and Sudafed is a brand name. Note that some products labelled for congestion contain a different decongestant, so check the active ingredient if you specifically want pseudoephedrine.
The wider class
About Decongestants
Pseudoephedrine belongs to the decongestants class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF: Pseudoephedrine hydrochloride.
- NICE CKS: Common cold.
- NICE CKS: Decongestants.
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