A sedating antihistamine for allergies and cold remedies
Brompheniramine
An older, sedating antihistamine used for allergy symptoms and commonly found in cough and cold products.
What is Brompheniramine?
Brompheniramine is an older, sedating antihistamine used to ease allergy symptoms such as a runny nose, sneezing and itchy, watery eyes, and it is often included in combination cough and cold remedies. Because it is a sedating type, the main thing to expect is drowsiness, so it can affect driving and is best not mixed with alcohol. It also has antimuscarinic effects, which can cause a dry mouth, blurred vision and constipation. Newer, non-drowsy antihistamines are usually preferred for everyday allergy relief.
Education and reference only. This is a plain-language guide to Brompheniramine — 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
Brompheniramine is an antihistamine, a medicine that blocks the effects of histamine, the chemical the body releases during allergic reactions. It belongs to the older, sedating group of antihistamines and is used to relieve allergy symptoms such as a runny or blocked nose, sneezing and itchy, watery eyes. It is most often found as one of the ingredients in combination cough and cold remedies. It is taken by mouth. Because it tends to cause drowsiness, non-drowsy antihistamines are usually chosen first for ongoing hay fever and allergies.
How it works
When the body reacts to an allergen such as pollen, it releases histamine, which causes sneezing, a runny nose, itching and watery eyes. Brompheniramine blocks the receptors that histamine acts on, so these symptoms are reduced. Unlike newer antihistamines, it crosses easily into the brain, which is why it causes drowsiness; this same property is why it is sometimes included in night-time cold remedies. It also blocks another chemical messenger (acetylcholine), giving it antimuscarinic effects such as drying up secretions, which can help a runny nose but also cause a dry mouth.
Company & origin
Originated / developed by: Various manufacturers.
An older sedating antihistamine used for allergy symptoms and often included in cough and cold remedies.
What it treats
Conditions Brompheniramine is used for
Practical use
How to take Brompheniramine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth as directed on the pack or by your prescriber, and check the other ingredients if it is part of a cough or cold product.
- Be aware it can make you drowsy, so avoid driving or operating machinery until you know how it affects you.
- Avoid alcohol and other sedating medicines while taking it, as these add to the drowsiness.
- Use it for short-term symptom relief, and consider a non-drowsy antihistamine for ongoing allergies.
- Tell your pharmacist about other medicines you take, especially other antihistamines or cold remedies, to avoid doubling up.
Weighing it up
Advantages & disadvantages of Brompheniramine
Advantages
- Eases allergy symptoms such as a runny nose, sneezing and itchy, watery eyes.
- Its drying and sedating effects can be helpful in night-time cough and cold remedies.
- Widely available and long established.
Disadvantages
- Commonly causes drowsiness, which can affect driving and daily activities.
- Antimuscarinic effects such as dry mouth, blurred vision and constipation are common.
- Generally less suitable than non-drowsy antihistamines for everyday, ongoing allergy relief.
Practical use
Good to know
The most important thing to understand about brompheniramine is that it is a sedating antihistamine, so drowsiness is common; this can affect your ability to drive or operate machinery safely, and it is made worse by alcohol and by other medicines that cause sleepiness. Its antimuscarinic effects can cause a dry mouth, blurred vision, constipation and difficulty passing urine, which is why it is used with caution in older people and in those with glaucoma or prostate problems. Because it is often part of a combination cough or cold product, it is worth checking the other ingredients, particularly so you do not accidentally double up on paracetamol or take a decongestant that does not suit you. For everyday allergy relief, a non-drowsy antihistamine is usually the better choice.
Who should not take it / use with caution
- People who have had a serious allergic reaction to brompheniramine should not take it.
- It is used with caution in older people and in those with glaucoma, an enlarged prostate or difficulty passing urine, because of its antimuscarinic effects.
- It should be used with care, or avoided, by people who need to drive or stay fully alert, and combined cold products should be checked for suitability in those with high blood pressure or heart problems.
Monitoring
- No routine monitoring is needed for short-term use.
- Watching for excessive drowsiness, particularly in older people.
- Reviewing whether a non-drowsy antihistamine would be more suitable for ongoing allergies.
Side effects
- Drowsiness and a feeling of being slowed down.
- Dry mouth, blurred vision, constipation or difficulty passing urine.
- Less commonly, dizziness, headache or, especially in children, restlessness or excitability.
Key interactions
- Alcohol and other sedating medicines add to its drowsiness.
- It adds to the antimuscarinic effects of other medicines that cause dry mouth and constipation.
- Combined cough and cold products may contain decongestants or paracetamol, so check the labels to avoid unwanted combinations or doubling up.
Available as: Tablets and liquids taken by mouth, often as part of combination cough and cold products.
Answers
Brompheniramine: frequently asked questions
What is brompheniramine used for?
It is a sedating antihistamine used to ease allergy symptoms such as a runny nose, sneezing and itchy, watery eyes, and it is often included in cough and cold remedies.
Will it make me drowsy?
Yes. It is a sedating antihistamine, so drowsiness is common, which can affect driving and daily activities and is made worse by alcohol.
Is it better than non-drowsy antihistamines?
For everyday allergy relief, newer non-drowsy antihistamines are usually preferred; brompheniramine's drowsiness can be a drawback, though it may suit night-time cold remedies.
Why does it dry my mouth?
Brompheniramine has antimuscarinic effects, which can cause a dry mouth, blurred vision and constipation alongside relieving allergy symptoms.
Can I take it with other cold remedies?
Check the labels first, as many cough and cold products already contain an antihistamine, a decongestant or paracetamol, and you should avoid doubling up.
The wider class
About Sedating (older) antihistamine
Brompheniramine belongs to the sedating (older) antihistamine 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
- NICE CKS
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