A three-active tablet containing paracetamol 500mg, pseudoephedrine 22.5mg, and diphenhydramine 12.5mg per tablet
For adults and children 10+ for cold and flu symptoms including congestion, cough, sneezing, runny nose, fever, headache, and body aches
Adult and 12+ dose: 2 tablets up to 4 times a day (max 8/24h); 10-11 years: 1 tablet up to 4 times a day; max 5 days without medical advice
Can cause drowsiness. Contraindicated with MAOI antidepressants, diabetes, high blood pressure, heart disease, hyperthyroidism, and angle-closure glaucoma
Available from Courier Pharmacy as a pharmacy medicine (P) with pharmacist support
Benylin 4 Flu Tablets are orange oral tablets. Each pack contains 24 tablets.
Each tablet contains three active ingredients. Paracetamol 500mg is an analgesic and antipyretic. Pseudoephedrine hydrochloride 22.5mg is a decongestant. Diphenhydramine 12.5mg is an older antihistamine that causes drowsiness.
Why the name refers to four symptoms, not four ingredients
The “4” in Benylin 4 Flu refers to the four main flu symptom groups treated. These are fever, nasal and sinus congestion, aches and pains, and cough with runny nose.
However, the tablet contains three active ingredients (not four). Each active covers one or more of these symptom groups.
For example, paracetamol handles fever and pain. Pseudoephedrine handles congestion. Diphenhydramine handles cough, sneezing, and runny nose.
A medicine with pack size restrictions
Benylin 4 Flu Tablets are a pharmacy medicine (P). They can only be supplied via pharmacies with pharmacist involvement.
Firstly, the pseudoephedrine content triggers UK Misuse of Drugs Regulations pack size limits. Pharmacies usually limit purchases to one pack per transaction.
Also, this is to prevent bulk buying for illicit methamphetamine manufacture. It does not affect normal medical use.
Furthermore, at Courier Pharmacy, our pharmacist may ask a few questions before supply. This check confirms the product is safe for your situation.
Key features
Form: orange oral tablets
Pack size: usually 24 tablets
Legal status: Pharmacy medicine (P), subject to Misuse of Drugs Regulations pack size limits
Storage: store below 25°C
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A three-active tablet targeting the four main flu symptom groups
Benylin 4 Flu Tablets are a well-known UK cold and flu remedy. Each orange film-coated tablet contains three active ingredients that target the four main symptom groups of colds and flu.
Firstly, paracetamol 500mg relieves pain, headache, muscular aches, and fever.
Also, pseudoephedrine hydrochloride 22.5mg is a decongestant. It helps unblock a stuffy nose and clear sinus congestion.
Furthermore, diphenhydramine hydrochloride 12.5mg is a first-generation antihistamine. It helps reduce cough, sneezing, and runny nose.
However, the “4” in the product name refers to the four symptom groups treated (fever, congestion, aches, cough and runny nose), not to four ingredients. The tablet actually contains three actives.
Also, Benylin 4 Flu Tablets are for adults and children aged 10 years and over. This is a lower minimum age than many other combined cold and flu products.
However, the diphenhydramine can cause drowsiness. Unlike Benylin Day and Night’s day tablet, this product is not non-drowsy.
Furthermore, it is a pharmacy medicine (P) because of the pseudoephedrine content. Pack size limits apply under the UK Misuse of Drugs Regulations.
Above all, an MHRA 2024 safety alert applies to all pseudoephedrine products. There is a rare but serious risk of PRES and RCVS (brain-blood-vessel conditions).
At Courier Pharmacy, our team can help you decide whether Benylin 4 Flu fits your symptoms and situation.
When to see a doctor rather than self-treat
Benylin 4 Flu Tablets are for short-term symptom relief only. However, some symptoms need medical assessment instead of continued self-treatment.
Sudden severe headache, seizures, sudden confusion, or visual disturbance. Stop the tablets and call 999 (possible PRES or RCVS from the pseudoephedrine)
Sudden abdominal pain, rectal bleeding, or blood in stools. Stop the tablets and seek urgent help (rare risk of ischaemic colitis from pseudoephedrine)
Chest pain, breathlessness, palpitations, or one-sided weakness. Call 999
Cold or flu symptoms lasting more than 5 days despite treatment, or symptoms that improve and then worsen
Thick coloured nasal discharge with high fever, severe facial pain, or dental pain (possible bacterial sinusitis)
Severe or widespread skin rash with pustules, blistering, or peeling. Stop the tablets and seek urgent help (possible AGEP)
Cough with blood, thick coloured phlegm, chest pain, or breathing difficulty. Seek medical assessment
Signs of paracetamol overdose (nausea, vomiting, abdominal pain, drowsiness). Contact NHS 111 or A&E even if you feel well
If you are pregnant, breastfeeding, over 60, take blood thinners, or have any of the medical conditions in the warnings section below, don’t take these without pharmacist or GP advice
Five key takeaways
Benylin 4 Flu Tablets contain three active ingredients per tablet: paracetamol 500mg (pain and fever), pseudoephedrine 22.5mg (decongestant), and diphenhydramine 12.5mg (antihistamine for cough, sneezing, runny nose).
Licensed for adults and children 10+ for cold and flu symptoms including congestion, cough, sneezing, runny nose, fever, headache, and body aches.
Dose: adults and children 12+ take 2 tablets up to 4 times a day (max 8 tablets in 24h). Not more than 5 days without medical advice.
Contraindicated in children under 10, diabetes, high blood pressure, heart disease, hyperthyroidism, phaeochromocytoma, angle-closure glaucoma, and with MAOI antidepressants (current or last 14 days), beta-blockers, or other decongestants.
Can cause drowsiness (diphenhydramine). Do not combine with other paracetamol, decongestant, antihistamine, or cold and flu products. Contains colours E104 and E110.
What are Benylin 4 Flu Tablets: overview
Where Benylin 4 Flu fits in cold and flu treatment
Cold and flu produce a mix of symptoms. Options include single-active products (paracetamol, ibuprofen, plain decongestant) and combined products like Benylin 4 Flu.
Firstly, Benylin 4 Flu’s specific niche is covering all four main symptom groups in one tablet. This suits patients with the full range of cold and flu symptoms.
However, if congestion is the only issue, plain Sudafed Decongestant Tablets or a nasal spray may fit better. If pain and fever dominate without congestion, plain paracetamol or ibuprofen may suffice.
Also, if drowsiness is unacceptable (e.g. daytime driving), a non-sedating option like Sudafed Sinus Pressure and Pain (paracetamol + pseudoephedrine, no antihistamine) fits better.
Benylin 4 Flu vs Benylin Day and Night
Both products come from Kenvue and share paracetamol as a core active. However, the format and use pattern differ.
Firstly, Benylin Day and Night comes as two different tablets: a non-drowsy white day tablet (paracetamol + pseudoephedrine 60mg) and a sedating blue night tablet (paracetamol + diphenhydramine 25mg).
Also, Benylin 4 Flu is a single orange tablet with all three actives (paracetamol + pseudoephedrine 22.5mg + diphenhydramine 12.5mg) at lower individual doses.
However, this means Benylin 4 Flu can cause drowsiness at any time of day, while Benylin Day and Night’s day tablet is non-drowsy.
Furthermore, Benylin 4 Flu is licensed from age 10; Benylin Day and Night is from 12. Choose based on symptoms, timing needs, and whether drowsiness matters.
Benylin 4 Flu vs Sudafed Sinus Pressure and Pain
Sudafed Sinus Pressure and Pain contains ibuprofen 200mg + pseudoephedrine 30mg. It is non-drowsy and does not include an antihistamine.
Firstly, Benylin 4 Flu uses paracetamol (not ibuprofen). This suits patients who cannot take ibuprofen (asthma, ulcer, kidney disease).
Also, Benylin 4 Flu adds diphenhydramine for cough, sneezing, and runny nose. Sudafed Sinus does not cover these.
However, Sudafed Sinus is non-drowsy, whereas Benylin 4 Flu can cause drowsiness. Sudafed Sinus is also higher-age (15+ vs 10+).
Short-term use only
Benylin 4 Flu Tablets are licensed for short-term (up to 5 days) symptom relief. Symptoms that persist beyond this need medical assessment.
Firstly, prolonged decongestant use raises cardiovascular strain. Prolonged sedating antihistamine use can cause daytime cognitive slowing.
Also, prolonged paracetamol use raises liver strain, particularly if combined with alcohol or existing liver problems.
However, chronic congestion or persistent cold-like symptoms have their own management. Ask your GP if symptoms recur or persist.
Self-medication with pharmacist support
Because Benylin 4 Flu is a pharmacy medicine, buying at Courier Pharmacy comes with pharmacist support. Firstly, this is a mandated feature of the pharmacy classification.
Also, the pharmacist can check that the product fits your symptoms and situation. They will confirm you are not on MAOI antidepressants, beta-blockers, or other interacting medicines.
However, if this product is not right for you, we will explain why. We will then suggest safer options (single-active products, non-sedating options, or a GP appointment).
Why choose Courier Pharmacy for your Benylin 4 Flu Tablets
Registered, independent, and patient-led
Courier Pharmacy is a UK-registered independent pharmacy. The General Pharmaceutical Council regulates us.
Firstly, even for a well-known pharmacy medicine like Benylin, pharmacist support matters. A short conversation can prevent avoidable harm.
Also, we treat every request as a chance to check that the product fits your situation. This is not a simple retail transaction.
As a result, buying these tablets from us comes with the reassurance that a UK-qualified pharmacist has thought about your specific case.
Dr Ada Jex-Cori, our brand pharmacist
Our brand pharmacist is Dr Ada Jex-Cori. She represents the spirit of what we do. Named for Ada Lovelace, Sophia Jex-Blake, and Gerty Cori, she stands for evidence-led, unafraid-of-questions medicine. Her message is straightforward. You’re not broken. The system is. We’re here to change that.
Care that keeps showing up
Pharmacy-medicine purchases are not one-off transactions when done properly. Firstly, we are here to answer follow-up questions if the product is not working as expected.
Also, if you notice unexpected side effects or your symptoms change, contact us. If symptoms persist beyond 5 days, we can help you think through the next step.
However, we will not sell repeated packs to someone who really needs medical assessment. That is not care, it is just retail.
Buy Benylin 4 Flu Tablets from Courier Pharmacy
Benylin 4 Flu Tablets are a pharmacy medicine (P). You can order at courierpharmacy.co.uk in the 24-tablet pack.
Add Benylin 4 Flu Tablets to your basket at courierpharmacy.co.uk
A brief pharmacist suitability check will be conducted before supply
Your order is dispensed and dispatched promptly
Follow the pack directions carefully. Contact us if you have questions
If this product is not right for your situation, we will explain why. Options include plain paracetamol, plain Sudafed Decongestant Tablets, Benylin Day and Night, or a GP appointment.
Above all, we will not dispense a pack that is not suitable for you just because it was requested.
Summary
A pharmacy-sold three-active tablet with paracetamol, pseudoephedrine, and diphenhydramine, targeting the four main cold and flu symptom groups.
Adult and 12+ dose: 2 tablets up to 4 times a day (max 8/24h). Max 5 days without medical advice.
Can cause drowsiness. Not suitable when driving, using machinery, or needing to stay alert.
Contraindicated with MAOI antidepressants (current or last 14 days), diabetes, high blood pressure, heart disease, hyperthyroidism, phaeochromocytoma, and glaucoma.
Subject to UK Misuse of Drugs Regulations pack size limits, usually one pack per transaction.
Active ingredients in Benylin 4 Flu Tablets
Paracetamol 500mg
Paracetamol is a widely-used analgesic (pain reliever) and antipyretic (fever reducer).
Firstly, the exact mechanism is not fully understood. It is thought to act primarily on the central nervous system, reducing prostaglandin production in the brain and spinal cord.
Also, at the 500mg dose per tablet (1000mg per adult dose of 2 tablets), paracetamol provides moderate pain relief and reduces fever. Onset is usually within 30 to 60 minutes.
However, paracetamol has a narrow safety margin in overdose. Doses just above the maximum can cause serious liver damage.
As a result, total daily paracetamol from all sources must not exceed 4 grams (4000mg) in adults. Benylin 4 Flu at maximum dose provides 4000mg per 24 hours, so it uses the full daily budget.
Pseudoephedrine hydrochloride 22.5mg
Pseudoephedrine is a synthetic sympathomimetic drug. It acts primarily on alpha-adrenergic receptors on blood vessels.
Firstly, at the 22.5mg dose (lower than the 60mg in plain Sudafed Decongestant Tablets), it works as an oral decongestant. It narrows blood vessels in the nasal and sinus lining.
Also, at 2 tablets per dose (45mg pseudoephedrine), this is closer to standard adult decongestant dosing.
However, this vasoconstricting effect is not confined to the nose. Some narrowing also occurs throughout the body. This can raise blood pressure and heart rate.
Furthermore, pseudoephedrine has been controlled in the UK under the Misuse of Drugs Regulations 2001 since 2007, due to its potential misuse as a methamphetamine precursor.
Diphenhydramine hydrochloride 12.5mg
Diphenhydramine is a first-generation H1 antihistamine of the ethanolamine class. It blocks histamine H1 receptors.
Firstly, blocking H1 receptors reduces the effects of histamine. This gives it some benefit for runny nose, sneezing, and catarrh.
Also, diphenhydramine has cough-suppressant effects. It reduces the tickle in the throat that triggers cough.
However, diphenhydramine crosses the blood-brain barrier readily. It causes noticeable sedation, which is why Benylin 4 Flu can make you drowsy.
Furthermore, diphenhydramine has anticholinergic effects. These include dry mouth, blurred vision, urinary retention, and (in older adults) confusion or falls.
Why the three-active combination is used
Cold and flu symptoms come from several different mechanisms. One tablet with three actives targets multiple symptoms at once.
Firstly, paracetamol addresses pain and fever. Also, pseudoephedrine addresses congestion. Furthermore, diphenhydramine addresses cough, sneezing, and runny nose.
As a result, a single tablet can relieve the full spectrum of cold and flu symptoms rather than requiring separate products.
However, the trade-off is receiving all three actives whether you need each one or not. If your symptoms are limited, single-active products may fit better.
What are Benylin 4 Flu Tablets for?
Cold and flu with multiple symptoms
Benylin 4 Flu is licensed for relief of symptoms associated with colds and flu, including nasal and sinus congestion, sneezing, runny nose, cough, fever, headache, and muscular aches and pains.
Firstly, this suits patients with the full mixed symptom picture. The three-active formulation covers most cold and flu symptom groups.
However, this product does not treat the underlying viral infection. Colds usually resolve on their own in 7 to 10 days.
Congestion with cough and runny nose
The pseudoephedrine addresses the blocked-nose component. The diphenhydramine helps with cough, sneezing, and runny nose.
Also, this dual action can help symptoms that keep recurring, particularly at night.
However, if the cough is chesty (productive with phlegm), an expectorant may fit better. If cough is dry, a specific cough suppressant may be more effective.
Fever with body aches
The paracetamol component reduces fever and relieves aches and pains associated with cold and flu.
Also, this often provides significant symptomatic improvement within 30 to 60 minutes.
However, if fever is very high (above 39°C), persistent, or accompanied by other serious symptoms, medical assessment is needed rather than continued OTC use.
What Benylin 4 Flu isn't for
This product is not for chronic congestion, chronic cough, chronic allergies, cold and flu prevention, or bacterial infections.
Also, it is not for children under 10, or for use during pregnancy or breastfeeding without medical advice.
However, if symptoms are severe, sudden, unusual, or accompanied by other concerning features (see the red flags above), this product is not the right response.
Furthermore, if you have diabetes, uncontrolled high blood pressure, severe heart disease, glaucoma, or take MAOI antidepressants, do not use these tablets.
How does Benylin 4 Flu Tablets work?
Paracetamol's analgesic and antipyretic action
Paracetamol works mainly on the central nervous system. Firstly, it is thought to reduce prostaglandin production in the brain and spinal cord.
Also, this reduces pain perception and lowers the raised body temperature set-point during infection.
However, paracetamol has minimal anti-inflammatory effect in peripheral tissues. This is why it is a weaker anti-inflammatory than ibuprofen or aspirin.
Furthermore, paracetamol does not cause the stomach irritation, cardiovascular strain, or platelet effects associated with NSAIDs.
Pseudoephedrine's alpha-adrenergic action
Pseudoephedrine narrows blood vessels in the nasal and sinus lining. Firstly, it binds to alpha-adrenergic receptors on the vessel walls.
Also, this makes the vessels tighten (vasoconstriction), reducing the swelling that causes a blocked nose. Sinus drainage improves too.
However, pseudoephedrine acts throughout the body, not just in the nose. This is why cardiovascular contraindications and cautions apply.
Furthermore, the lower 22.5mg dose per tablet spreads the pseudoephedrine effect across multiple daily doses, providing steadier coverage.
Diphenhydramine's antihistamine, cough-suppressant, and sedative action
Diphenhydramine blocks histamine H1 receptors. Firstly, this reduces the effects of histamine released during colds and flu.
Also, this eases runny nose, sneezing, and mild throat itch. Diphenhydramine also has direct cough-suppressant effects on the cough reflex.
However, diphenhydramine crosses the blood-brain barrier readily. It blocks H1 receptors in the brain, where histamine helps maintain wakefulness.
Furthermore, blocking these central H1 receptors induces sedation. This is why Benylin 4 Flu can make you drowsy.
Why the three-active tablet works
Cold and flu symptoms come from three different mechanisms. Different symptoms respond to different actives.
Firstly, paracetamol handles inflammation-driven pain and fever. Also, pseudoephedrine handles vascular congestion. Furthermore, diphenhydramine handles histamine-driven runny nose and cough.
As a result, a single tablet targets multiple symptom pathways at once. This is the value of a combined product.
How to take Benylin 4 Flu Tablets
Adult and 12+ dose
Take 2 tablets with water, up to 4 times a day. Leave at least 4 hours between doses.
However, do not take more than 8 tablets (4 doses) in any 24-hour period. Do not exceed the stated dose.
Also, do not take for more than 5 days without medical advice.
Children 10-11 years dose
Take 1 tablet with water, up to 4 times a day. Leave at least 4 hours between doses.
Do not exceed 4 tablets in 24 hours. Not to be given for more than 5 days without medical advice.
However, if you are unsure about giving these tablets to a 10 or 11 year old, ask the pharmacist or GP first.
Children under 10 (not for use)
Benylin 4 Flu Tablets are not for children under 10 years of age. Younger children need age-appropriate options.
However, for cold and flu symptoms in children under 10, paediatric paracetamol (Calpol) or ibuprofen for pain and fever, plus saline nasal drops for congestion, are the standard options.
How quickly the tablets work
The paracetamol usually starts to reduce pain and fever within 30 to 60 minutes. The pseudoephedrine relieves congestion within about 30 minutes.
Also, peak effect for all actives is reached at about 1 to 2 hours. The effect usually lasts around 4 to 6 hours per dose.
However, the diphenhydramine's sedative effect can start within 30 to 60 minutes and may persist longer.
Timing during the day
Because Benylin 4 Flu can cause drowsiness, timing matters. Firstly, avoid taking a dose before driving, cycling, or using machinery.
Also, avoid it if you need to stay alert for work, study, or childcare. Consider a non-sedating option in those situations.
However, an evening dose taken well before bedtime can help you sleep through cold and flu symptoms. But do not use these tablets as a general sleep aid.
Missed doses and stopping
These tablets are taken as needed, not on a fixed schedule. So there is no missed-dose concern in the usual sense.
Also, you can stop the tablets whenever your symptoms have resolved. There is no need to taper.
However, if you find yourself needing them for more than 5 days, medical assessment is warranted. The underlying cause of ongoing symptoms matters.
Do not take with other paracetamol, decongestants, or antihistamines
Above all, do not take Benylin 4 Flu alongside any other product containing paracetamol. This includes plain paracetamol tablets, Panadol, Anadin Extra, Lemsip, Beechams All-in-One, Day Nurse, Night Nurse, Benylin Day and Night, co-codamol, or co-dydramol.
Also, do not combine with any other product containing pseudoephedrine, phenylephrine, or ephedrine (Sudafed products, Actifed, Beechams cold products, Nurofen Cold and Flu variants).
Furthermore, do not combine with other sedating antihistamines (chlorphenamine, promethazine, cyclizine) or with non-sedating antihistamines during the day.
However, plain ibuprofen for extra pain or inflammation can be taken alongside, following ibuprofen's own directions.
If in doubt, ask the pharmacist before combining any cold, flu, pain, or allergy medicines.
Warnings and precautions for Benylin 4 Flu Tablets
MHRA safety alert: PRES and RCVS (rare but serious)
Above all, the MHRA issued a safety alert in February 2024 for pseudoephedrine-containing medicines. Rare but serious cases of PRES and RCVS have been reported.
Firstly, PRES stands for posterior reversible encephalopathy syndrome. RCVS stands for reversible cerebral vasoconstriction syndrome.
Also, both conditions involve reduced blood supply to the brain. Symptoms include sudden severe headache, seizures, sudden confusion, visual disturbances, or slurred speech.
However, if any of these symptoms develop while taking the tablets, stop immediately. Seek urgent medical assessment (call 999 for severe symptoms).
Ischaemic colitis (rare but serious)
Ischaemic colitis has been reported with pseudoephedrine. This is a condition where reduced blood flow damages part of the large bowel.
Firstly, symptoms include sudden abdominal pain, rectal bleeding, bloody stools, or unusual bowel changes.
However, if these develop while taking the tablets, stop immediately and seek medical assessment.
AGEP (rare severe skin reaction)
Acute generalised exanthematous pustulosis (AGEP) is a rare but serious skin reaction reported with pseudoephedrine-containing products.
Also, AGEP usually appears within the first 2 days of treatment. Features include fever with numerous small pustules on widespread reddened skin.
However, if a severe rash appears while taking the tablets, stop them and seek urgent medical assessment.
Drowsiness, driving, and machinery
Benylin 4 Flu can cause significant sedation from the diphenhydramine. Firstly, do not drive, ride a bicycle, or use machinery after taking these tablets.
Also, sedation can persist between doses. Caution with next-day driving is warranted especially if you notice residual drowsiness.
However, driving while impaired by prescription or OTC medicines is a criminal offence in the UK. This is under the Road Traffic Act 1988.
As a result, take Benylin 4 Flu only when you can commit to being off the road until you are fully alert.
Cardiovascular contraindications
Benylin 4 Flu is contraindicated in severe or uncontrolled high blood pressure, severe coronary artery disease, and heart disease.
Firstly, pseudoephedrine's vasoconstricting effect can worsen all of these conditions. Rarely, it can precipitate serious events like hypertensive crisis, myocardial infarction, or stroke.
However, if you take any regular medicine for high blood pressure or heart conditions, disclose this before buying.
Diabetes (contraindicated)
Benylin 4 Flu is contraindicated in diabetes. Pseudoephedrine can raise blood glucose levels through its sympathomimetic effects.
However, if you have diabetes and need cold or flu symptom relief, ask the pharmacist for safer options.
Hyperthyroidism (contraindicated)
Patients with an overactive thyroid should not use these tablets. Sympathomimetic drugs can compound the effects of excess thyroid hormone.
Angle-closure glaucoma and prostatic hypertrophy (contraindicated)
These tablets are contraindicated in narrow-angle glaucoma. Both pseudoephedrine and diphenhydramine can precipitate an acute glaucoma attack in susceptible patients.
Also, they are contraindicated in prostatic hypertrophy with urinary retention. Both actives can worsen urinary retention.
Phaeochromocytoma (contraindicated)
Contraindicated in phaeochromocytoma (a rare tumour that affects heart rate and blood pressure). Pseudoephedrine can precipitate serious cardiovascular events in these patients.
MAOI antidepressants and beta-blockers (contraindicated)
Above all, do not take these tablets if you are on an MAOI antidepressant, or within 14 days of stopping one.
Also, MAOIs include phenelzine, isocarboxazid, tranylcypromine, and moclobemide. Rasagiline and selegiline (Parkinson's medicines) carry the same concern.
Furthermore, do not combine with beta-blockers (propranolol, atenolol, bisoprolol, metoprolol). The combination with pseudoephedrine can cause paradoxical high blood pressure.
Paracetamol overdose and HAGMA
Paracetamol overdose can cause serious liver damage. Doses just above the maximum can be harmful.
Also, high anion gap metabolic acidosis (HAGMA) due to pyroglutamic acidosis has been reported in patients with severe illness, severe renal impairment, sepsis, or malnutrition, treated with paracetamol.
However, if you have any of these conditions, discuss with the pharmacist or GP before use.
Severe renal or hepatic impairment (caution)
Use with caution in severe kidney or liver disease. Paracetamol is metabolised by the liver, and severe impairment raises toxicity risk.
Also, pseudoephedrine is excreted by the kidneys, so accumulation can occur in severe renal impairment. Diphenhydramine metabolism is affected by liver function.
Alcohol (compounded sedation)
Avoid alcohol while taking these tablets. Firstly, alcohol compounds the sedating effect of the diphenhydramine.
Also, alcohol raises the risk of paracetamol-related liver injury, particularly with regular use.
Furthermore, alcohol has its own cardiovascular effects that can add to pseudoephedrine's blood-pressure-raising effect.
Pregnancy (not recommended)
Benylin 4 Flu is not recommended during pregnancy without medical advice. Pseudoephedrine has been linked to a small increased risk of certain birth defects in the first trimester.
However, paracetamol alone at the lowest effective dose is generally preferred for pain and fever in pregnancy. Ask your midwife, GP, or pharmacist.
Breastfeeding (not recommended)
These tablets are not recommended during breastfeeding without medical advice. Pseudoephedrine passes into breast milk and can reduce milk production.
Also, diphenhydramine can pass into milk and cause infant sedation. Ask your midwife, GP, or pharmacist for guidance.
Elderly patients (caution)
Use with caution in adults over 60. Firstly, older adults are more sensitive to pseudoephedrine's cardiovascular effects.
Also, they are more susceptible to diphenhydramine's sedative and anticholinergic effects. This includes falls, confusion, urinary retention, and constipation.
However, if these tablets are considered in older adults, discuss with the pharmacist. Safer options usually exist.
Duration of use (short-term only)
Do not take these tablets for more than 5 days without medical advice. Ongoing symptoms need medical assessment.
Also, prolonged pseudoephedrine use can cause tolerance and cardiovascular strain. Prolonged sedating antihistamine use can cause daytime cognitive slowing.
Colouring agents E104 and E110
Benylin 4 Flu Tablets contain quinoline yellow (E104) and sunset yellow (E110). These colour additives may cause allergic reactions in susceptible patients.
However, if you have a history of allergy or intolerance to food colours, discuss with the pharmacist before use.
Side effects of Benylin 4 Flu Tablets
Common side effects
Common side effects come from all three actives. Firstly, drowsiness from the diphenhydramine is very common.
Also, dry mouth, dry eyes, mild dizziness, and mild constipation are common anticholinergic effects.
However, insomnia (if taken too late), restlessness, and mild palpitations can come from the pseudoephedrine.
Furthermore, mild nausea or stomach upset can occur from any of the three actives.
Less common but significant side effects
Some side effects need attention. Firstly, palpitations, feeling your heart racing, or a noticeable rise in blood pressure warrant stopping the tablets.
Also, difficulty passing urine (particularly in men over 50) may indicate developing acute urinary retention.
However, next-day drowsiness or cognitive slowing that affects daily function warrants stopping the tablets.
Furthermore, paradoxical excitation (increased alertness or agitation rather than sedation) can occur, particularly in older adults or children.
Serious side effects requiring urgent help
Above all, seek urgent medical help for signs of PRES or RCVS. These include sudden severe headache, seizures, sudden confusion, visual disturbances, or slurred speech.
Also, seek help for signs of stroke: face drooping, arm weakness, speech difficulty (FAST). Call 999.
However, severe chest pain, breathlessness, or palpitations need urgent assessment. Signs of hypertensive crisis include very severe headache, chest pain, or trouble breathing.
Furthermore, signs of severe allergic reaction (facial or throat swelling, breathing difficulty, widespread rash) need 999.
Also, severe skin reactions with pustules, blistering, or peeling need urgent assessment (possible AGEP).
Signs of paracetamol overdose (nausea, vomiting, abdominal pain, drowsiness, confusion) need urgent assessment even if only slightly above the maximum dose.
Above all, do not take these tablets if you are on an MAOI antidepressant, or within 14 days of stopping one.
Also, MAOIs include phenelzine, isocarboxazid, tranylcypromine, and moclobemide. Linezolid (an antibiotic) carries the same concern.
Furthermore, rasagiline and selegiline (used for Parkinson's disease) have MAOI-like activity and should not be combined.
Beta-blockers (contraindicated)
Do not combine with beta-blockers (propranolol, atenolol, bisoprolol, metoprolol, and others). Firstly, the combination with pseudoephedrine can cause paradoxical high blood pressure.
Also, this is because beta-blockade leaves pseudoephedrine's alpha-adrenergic vasoconstricting effect unopposed.
Other pseudoephedrine, phenylephrine, or decongestant products
Do not take alongside any other product containing pseudoephedrine, phenylephrine, ephedrine, or another systemic decongestant.
Also, this includes Sudafed products, Actifed, Beechams cold products, Day Nurse, Lemsip, and Nurofen Cold and Flu variants.
However, this also includes topical decongestant nasal sprays (xylometazoline, oxymetazoline).
Other paracetamol products
Above all, do not combine with other paracetamol-containing products. This includes plain paracetamol, Panadol, Anadin Extra, Lemsip Max, Beechams All-in-One, Day Nurse, Night Nurse, Benylin Day and Night, co-codamol, and co-dydramol.
Also, paracetamol overdose from combined products is a common cause of accidental liver damage. Always check ingredient labels.
Other sedating antihistamines
Do not combine with other sedating antihistamines (chlorphenamine, promethazine, cyclizine). This compounds sedation and anticholinergic effects.
Avoid alcohol while taking these tablets. Alcohol compounds sedation from the diphenhydramine.
Also, other CNS depressants add to sedation and (rarely) breathing depression risk. Examples include benzodiazepines (diazepam, lorazepam), Z-drugs (zolpidem, zopiclone), and opioid painkillers (morphine, oxycodone, tramadol, codeine).
Warfarin (long-term paracetamol interaction)
Regular paracetamol use can enhance the anticoagulant effect of warfarin, raising INR and bleeding risk.
However, occasional use is usually acceptable. Discuss with your anticoagulation clinic if you take warfarin regularly.
Metoclopramide, domperidone, and cholestyramine
Metoclopramide and domperidone speed up paracetamol absorption. Cholestyramine slows it down.
However, these interactions are usually clinically minor. Ask your pharmacist if you take any of these medicines regularly.
Tricyclic antidepressants
Use with caution with tricyclic antidepressants (amitriptyline, nortriptyline, imipramine, clomipramine).
Also, tricyclics can enhance the pressor effect of pseudoephedrine, raising blood pressure and cardiac arrhythmia risk.
However, tricyclics also add to diphenhydramine's anticholinergic effects.
Frequently asked questions about Benylin 4 Flu Tablets
Why is it called "4 Flu" if it only has 3 actives?
The "4" refers to the four main flu symptom groups treated: fever, congestion, aches and pains, and cough with runny nose.
However, the tablet contains three active ingredients (paracetamol, pseudoephedrine, diphenhydramine), each covering one or more of these symptom groups.
How quickly do these tablets work?
The paracetamol usually starts to reduce pain and fever within 30 to 60 minutes. The pseudoephedrine relieves congestion within about 30 minutes.
However, the diphenhydramine's sedative effect can start within 30 to 60 minutes. Full symptom improvement usually within 1 to 2 hours.
Will Benylin 4 Flu make me drowsy?
Yes, likely. The diphenhydramine in Benylin 4 Flu causes sedation. Do not drive, ride a bicycle, or use machinery after taking these tablets.
However, individual sensitivity varies. Some patients notice only mild drowsiness; others become significantly sedated.
Can I drive after taking these tablets?
No, not until you are fully alert. Firstly, driving while impaired by prescription or OTC medicines is a criminal offence in the UK under the Road Traffic Act 1988.
Also, if you need to drive during the day, consider a non-sedating option like Sudafed Sinus Pressure and Pain.
Can I take Benylin 4 Flu with alcohol?
No. Alcohol substantially compounds the sedating effect of the diphenhydramine. This can cause impaired coordination, judgement, and (rarely) breathing depression.
Also, alcohol raises the risk of paracetamol-related liver injury.
Can I take these with other cold and flu products?
No, do not combine with other cold and flu remedies without pharmacist advice. Firstly, most contain paracetamol, pseudoephedrine, or an antihistamine. Combining overloads the doses.
However, plain ibuprofen for extra pain or inflammation can be taken alongside, following ibuprofen's own directions.
Can I take these with paracetamol?
No. Benylin 4 Flu already contains paracetamol 500mg per tablet. Adding more paracetamol from another product can lead to overdose and serious liver damage.
However, always check the ingredients of any other pain or cold medicine before combining with Benylin 4 Flu.
Can children take these tablets?
Yes, children aged 10 and over can take Benylin 4 Flu. Children 10-11 take 1 tablet up to 4 times a day. Children 12+ and adults take 2 tablets up to 4 times a day.
However, children under 10 must not take these tablets. Younger children need age-appropriate options like paediatric paracetamol.
Can I take these during pregnancy or breastfeeding?
Not without medical advice. These tablets are not recommended in pregnancy or breastfeeding.
However, paracetamol alone at the lowest effective dose is generally preferred for pain and fever in pregnancy. Ask your midwife, GP, or pharmacist.
How long can I take these tablets for?
Do not take these tablets for more than 5 days without medical advice. Ongoing symptoms need medical assessment.
What are PRES and RCVS?
PRES stands for posterior reversible encephalopathy syndrome. RCVS stands for reversible cerebral vasoconstriction syndrome.
Also, both are rare brain-blood-vessel conditions highlighted by the MHRA in 2024 for pseudoephedrine-containing medicines.
However, symptoms include sudden severe headache, seizures, sudden confusion, visual disturbance, or slurred speech. If any develop, stop the tablets and seek urgent medical assessment.
What is ischaemic colitis?
Ischaemic colitis is a condition where reduced blood flow damages part of the large bowel. It has been rarely reported with pseudoephedrine.
Also, symptoms include sudden abdominal pain, rectal bleeding, and bloody stools. Stop the tablets and seek medical assessment if these develop.
What's the difference between this and Benylin Day and Night?
Benylin Day and Night is a two-tablet pack: a non-drowsy white day tablet with paracetamol + pseudoephedrine 60mg, and a sedating blue night tablet with paracetamol + diphenhydramine 25mg.
However, Benylin 4 Flu is a single orange tablet with all three actives at lower individual doses (paracetamol + pseudoephedrine 22.5mg + diphenhydramine 12.5mg).
Also, Benylin 4 Flu can cause drowsiness at any time, while Benylin Day and Night's day tablet is non-drowsy. Benylin 4 Flu is licensed from age 10; Day and Night from 12.
Can I take these if I have high blood pressure or heart disease?
No, these tablets are contraindicated in high blood pressure, severe coronary artery disease, and heart disease.
However, safer options exist. Ask the pharmacist for guidance.
Can I take these if I have diabetes?
No, these tablets are contraindicated in diabetes. Pseudoephedrine can raise blood glucose levels.
However, for cold and flu symptoms in diabetes, plain paracetamol for pain and fever, plus saline nasal spray for congestion, are safer options.
Are these tablets addictive?
They are not addictive in the way opioid painkillers can be. Firstly, at therapeutic doses, none of the three actives cause chemical dependence.
However, tolerance to the sedative effect of diphenhydramine can develop with regular use. Stick to short-term use.
What if I've taken too many tablets?
Contact NHS 111 or A&E immediately. Firstly, paracetamol overdose can cause serious liver damage even at doses just above the maximum.
Also, pseudoephedrine overdose can cause severe cardiovascular effects and CNS stimulation. Diphenhydramine overdose can cause severe sedation, breathing depression, and (rarely) seizures.
However, take the packaging with you so medical staff can see exactly what and how much you have taken.
Do I need a prescription for these tablets from Courier Pharmacy?
No. Benylin 4 Flu Tablets are a pharmacy medicine (P), not prescription-only.
However, this means they can be supplied without a prescription but only via a pharmacy with pharmacist involvement. UK pack size limits also apply.
Disclaimer
Disclaimer: This information is for education only and isn't a substitute for personal medical advice. Always follow the packaging directions, and ask your pharmacist or GP if you're unsure whether Benylin 4 Flu Tablets are suitable for you.
