Pharmacy Guide

Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.

Pharmacy Guide

Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.

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Benylin Day & Night Tablets

⚠ This medicine appears to have been discontinued

The electronic medicines compendium (emc) no longer publishes a Summary of Product Characteristics for this product, which usually means it is no longer marketed in the UK. The patient leaflet below is kept for reference, but the product may not be available.

If you were prescribed this medicine, other products containing Diphenhydramine hydrochloride, Paracetamol, Pseudoephedrine hydrochloride may still be available. Do not stop your treatment — ask your pharmacist or GP what to use instead.

Active substance: Diphenhydramine hydrochloride, Paracetamol, Pseudoephedrine hydrochloride

Equivalent medicines (same active substance, strength and form)

Source: electronic medicines compendium (emc)
Official leaflet: Read the PIL on emc

How to take it

this medicine Check the table that follows to see how much medicine to take.

For oral use only. Do not take more medicine than the label tells you to.  Take with a glass of water.  

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Children under 12 years old

Do not give to children under 12 years old.

Adults and children aged 12 years and over Age

Dose

Adults and children Day time aged 12 years 1 white tablet every 4-6 and over hours, up to 3 times a day (one tablet in the morning at mid-day and in the afternoon). Night time 1 blue tablet to be taken at night. Do not take more than 3 white tablets a day. Take only 1 tablet at a time and only at the times of day described in the table.  Do not take the night time tablets during the day.  If symptoms persist or worsen, stop use and talk to your doctor.  

If anyone has too much Talk to a doctor at once if you take too much of this medicine even if you feel well. This is because too much paracetamol can cause delayed, serious liver damage.

If you forget to take the medicine If you forget to take a dose, take the next dose when needed provided that the last dose was taken at least 4 hours ago. Do not take a double dose.

4 Possible side-effects Like all medicines Benylin Day and Night Tablets can have side-effects, although not everybody gets them.

If you experience any of the following, stop using this medicine and seek immediate medical help: 

Reduced blood flow to the heart which can cause angina (discomfort or pain in the chest, neck, back,

jaw, shoulders or arms), or heart attack. Stroke (weakness of the face, arms or legs, or speech problems).  Sudden onset of fever, reddening of the skin, or many small pustules (possible symptoms of Acute Generalized Exanthematous Pustulosis – AGEP) may occur within the first 2 days of treatment with this medicine (see section 2).  Sudden onset of severe headache, nausea, vomiting, confusion, fits, visual disturbances.  Swelling of the face, lips, mouth, tongue or throat which may cause difficulty in swallowing or breathing.  Allergic reactions including skin rashes such as hives (which may be severe and include blistering or peeling of the skin) and itching.  Feeling unusually tired, unexpected bruising or bleeding and getting more infections (such as colds) than normal.  Hallucinations or paranoid delusions (seeing or hearing things that are not there, irrational thoughts or feelings).  Inflammation of the colon due to insufficient blood supply (ischaemic colitis). Symptoms may include sudden abdominal pain or rectal bleeding.  Sudden loss or reduction of vision which may be due to reduced blood flow to the optic nerve (Ischaemic optic neuropathy). 

If you experience any of the following, stop using this medicine and talk to your doctor: 

Trouble passing water (especially in men with prostate problems)

Other effects which may occur include:

Very Common (may affect more than 1 in 10 people)  Headache or drowsiness

Common (may affect up to 1 in 10 people)  Difficulty sleeping, nervousness or dizziness

Difficulty performing tasks Dry mouth, thickened mucus or nausea  Blurred vision  Unusual weakness  

Uncommon (may affect up to 1 in 100 people)  Irritability or confusion  Tinnitus (a persistent noise in the ears) Rare (may affect up to 1 in 1000 people)  Depression  Tremor, shakiness or slurred speech  Low blood pressure  An increased awareness of the heartbeat (palpitations)  Sleep disturbances Other effects which may occur but it is unknown how often  Serious conditions affecting bloodvessels in the brain known as posterior reversible encephalopathy syndrome (PRES)and reversible cerebral vasoconstriction syndrome (RCVS).  Anxiety, restlessness or feelings of extreme happiness  Tingling or numbness of the hands or feet (pins and needles)  A fast or irregular heartbeat  High blood pressure  Dry nose  Vomiting  Chest tightness or discomfort  Pain when passing water  A serious condition that can make blood more acidic (called metabolic acidosis), in patients with severe illness using paracetamol (see section 2). Very rare cases of serious skin reactions have been reported with paracetamol. Stop using Benylin Day & Night Tablets immediately and seek urgent medical attention if you develop symptoms, that may be signs of posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome(RCVS). turn over

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These include:  severe headache with a sudden onset  feeling sick  vomiting  confusion  seizures changes in vision Reporting of side effects If you get any side-effects, talk to your doctor, pharmacist or nurse. This includes any possible side-effects not listed in this leaflet. You can also report

Possible side effects

directly via the Yellow Card Scheme at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side-effects, you can help provide more information on the safety of this medicine.

5 Storing this medicine Do not store above 25oc. Store in the original packaging. Keep this medicine out of the sight and reach of children. Do not use this medicine after the expiry date which is stated on the carton after 'Expiry'. The expiry date refers to the last day of that month. Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. These measures will help to protect the environment

Day Tablets: Pregelatinised maize starch, povidone, crospovidone, stearic acid, microcrystalline cellulose, croscarmellose sodium and magnesium stearate. Night Tablets: Microcrystalline cellulose, maize starch, sodium starch glycollate, pregelatinised maize starch, hydroxypropylcellulose, croscarmellose sodium, stearic acid, magnesium stearate and are coated with hypromellose, indigo carmine (E132), titanium dioxide (E171) and propylene glycol.

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What the medicine looks like Benylin Day and Night Tablets are 12 white oblong day-time tablets and 4 blue round night-time tablets, available in packs of 16 tablets. Marketing Authorisation holder: McNeil Products Ltd, High Wycombe, Buckinghamshire, HP12 4EG, UK. Manufacturer: JNTL Consumer Health (France) SAS, Domaine de Maigremont, 27100 Val de Reui1, France. This leaflet was revised January 2025. Benylin is a registered trade mark. McNeil Products Limited 2025 ©

6 Further information What's in this medicine? The active ingredients in Benylin Day and Night Tablets are: Day Tablets: 500 mg Paracetamol and 60 mg Pseudoephedrine hydrochloride. Night Tablets: 500 mg Paracetamol and 25 mg Diphenhydramine hydrochloride. Other ingredients are:

360141H

Frequently asked questions about Benylin Day & Night Tablets

How do I take Benylin Day & Night Tablets?

Benylin Day & Night Tablets comes as tablet. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.

What is the active substance in Benylin Day & Night Tablets?

The active substance in Benylin Day & Night Tablets is diphenhydramine hydrochloride, paracetamol, pseudoephedrine hydrochloride.

Are there equivalent medicines to Benylin Day & Night Tablets?

Medicines with the same active substance, strength and form include: Benylin Four Flu tablets. They are interchangeable only if your prescriber or pharmacist says so.

Where does this information come from?

This leaflet reproduces the patient information leaflet approved for Benylin Day & Night Tablets, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.

Can I get Benylin Day & Night Tablets without a prescription?

Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.

About this leaflet

The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.

  • Source: electronic medicines compendium (emc), Datapharm
  • Active substance: diphenhydramine hydrochloride, paracetamol, pseudoephedrine hydrochloride
  • Official document: view the original leaflet on emc →
Medical disclaimer: This page is for information only and does not replace advice from your doctor or pharmacist. Always read the leaflet supplied with your medicine. If you are unwell, call NHS 111; in an emergency, call 999.

Medicines with the same active substance: Diphenhydramine hydrochloride (17 medicines), Diphenhydramine hydrochloride, paracetamol, pseudoephedrine hydrochloride (2 medicines), Paracetamol (185 medicines), Pseudoephedrine hydrochloride (19 medicines)
See every medicine containing this substance, or browse the full A–Z of active substances.
⚕For healthcare professionals — Summary of Product Characteristics (SmPC)Full SmPC: dosage, interactions, contraindications, warnings+
Technical information intended for healthcare professionals (doctors and pharmacists). The Summary of Product Characteristics (SmPC) is the official document approved by the MHRA/EMA. It does not replace the patient leaflet or a doctor’s advice.

4.1. Therapeutic indications

For the relief of the symptoms associated with colds and influenza.

4.2. Posology and method of administration

Posology

Adults and Children over 12 years

Four tablets should be taken daily:

One white tablet to be taken every 4 to 6 hours during the day (no more than three white tablets a day).

One blue tablet to be taken at night.

Take only one tablet at a time and only at the times of day indicated on the pack. Do not take the nighttime tablets during the day.

Elderly

As for adults (see Pharmacokinetics).

Children

Not recommended for children under 12 years of age.

Method of Administration

For oral use

Hepatic Dysfunction

Caution should be exercised when administering this medicine to patients with severe hepatic impairment.

Renal Dysfunction

Caution should be exercised when administering this medicine to patients with moderate renal impairment.

4.3. Contraindications

Use in individuals with known hypersensitivity to diphenhydramine paracetamol, pseudoephedrine or to any of the excipients listed in section 6.1.

Concomitant use of other sympathomimetic decongestants, beta-blockers or monoamine oxidase inhibitors (MAOIs), or within 14 days of stopping MAOI treatment (see section 4.5). The concomitant use of MAOIs may cause a rise in blood pressure and/or hypertensive crisis.

Cardiovascular disease including hypertension

Diabetes mellitus

Phaeochromocytoma

Hyperthyroidism

Closed angle glaucoma

Severe acute or chronic kidney disease/renal failure

4.4. Special warnings and precautions for use

Diphenhydramine may enhance the sedative effects of central nervous system depressants including alcohol, sedatives, opioid analgesics, antipsychotics and tranquilizers. Alcoholic beverages should be avoided while taking this product.

If any of the following occur, Benylin Day and Night Tablets should be stopped:

• Hallucinations

• Restlessness

• Sleep disturbances

Severe Skin reactions: Severe skin reactions such as acute generalized exanthematous pustulosis (AGEP) may occur with pseudoephedrine-containing products. This acute pustular eruption may occur within the first 2 days of treatment, with fever, and numerous, small, mostly non-follicular pustules arising on a widespread oedematous erythema and mainly localized on the skin folds, trunk, and upper extremities. Patients should be carefully monitored. If signs and symptoms such as pyrexia, erythema, or many small pustules are observed, administration of this medicine should be discontinued, and appropriate measures taken if needed.

Ischaemic colitis: Some cases of ischaemic colitis have been reported with pseudoephedrine. Pseudoephedrine should be discontinued, and medical advice sought if sudden abdominal pain, rectal bleeding or other symptoms of ischaemic colitis develop.

Ischaemic optic neuropathy: Cases of ischaemic optic neuropathy have been reported with pseudoephedrine. Pseudoephedrine should be discontinued if sudden loss of vision or decreased visual acuity such as scotoma occurs.

Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS)

Cases of PRES and RCVS have been reported with the use of pseudoephedrine-containing products (see section 4.8). The risk is increased in patients with severe or uncontrolled hypertension, or with severe acute or chronic kidney disease/renal failure (see section 4.3).

Pseudoephedrine should be discontinued and immediate medical assistance sought if the following symptoms occur: sudden severe headache or thunderclap headache, nausea, vomiting, confusion, seizures and/or visual disturbances. Most reported cases of PRES and RCVS resolved following discontinuation and appropriate treatment.

Patients with the following conditions should be advised to consult a physician before using this product:

• Acute or chronic asthma, a persistent or chronic cough such as occurs with chronic bronchitis or emphysema or where cough is accompanied by excessive secretions

• Difficulty in urination, urinary retention and/or prostatic hyperplasia

• Patients with thyroid disease who are receiving thyroid hormones

Use with caution in patients with susceptibility to angle-closure, severe hepatic impairment, moderate to severe renal impairment (particularly if accompanied by cardiovascular disease), or occlusive vascular disease. The hazards of overdose are greater in those with non-cirrhotic alcoholic liver disease.

Cases of high anion gap metabolic acidosis (HAGMA) due to pyroglutamic acidosis have been reported in patients with severe illness such as severe renal impairment and sepsis, or in patients with malnutrition or other sources of glutathione deficiency (e.g. chronic alcoholism), who were treated with paracetamol at therapeutic dose for a prolonged period or a combination of paracetamol and flucloxacillin. If HAGMA due to pyroglutamic acidosis is suspected, prompt discontinuation of paracetamol and close monitoring is recommended. The measurement of urinary 5-oxoproline may be useful to identify pyroglutamic acidosis as underlying cause of HAGMA in patients with multiple risk factors.

Do not use with any other product containing diphenhydramine, including topical formulations used on large areas of skin.

Taking this product with other paracetamol-containing products, could lead to overdose and should therefore be avoided.

May cause drowsiness. This product should not be used to sedate a child.

This medicine contains less than 1 mmol sodium (23 mg) per dose, that is to say essentially 'sodium-free'.

Risks of abuse

Pseudoephedrine carries the risk of abuse. Increased doses may ultimately produce toxicity. Continuous use can lead to tolerance resulting in an increased risk of overdosing. The recommended maximum dose and treatment duration should not be exceeded (see section 4.2).

4.5. Interaction with other medicinal products and other forms of interaction

MAOIs (see section 4.3) and/or RIMAs: Pseudoephedrine exerts its vasoconstricting properties by stimulating α-adrenergic receptors and displacing noradrenaline from neuronal storage sites. Since monoamine oxidase inhibitors (MAOIs) impede the metabolism of sympathomimetic amines and increase the store of releasable noradrenaline in adrenergic nerve endings, MAOIs may potentiate the pressor effect of pseudoephedrine. This product should not be used in patients taking MAOIs or within 14 days of stopping treatment as there is a risk of serotonin syndrome (diphenhydramine) or hypertensive crisis (pseudoephedrine).

Moclobemide: Risk of hypertensive crisis.

Appetite suppressants and amphetamine-like psychostimulants: Concomitant use of this product with sympathomimetic agents such as decongestants, tricyclic antidepressants, appetite suppressants and amphetamine-like psychostimulants, may cause a rise in blood pressure.

Antihypertensives: Because of its pseudoephedrine content, this product may partially reverse the hypotensive action of antihypertensive drugs which interfere with sympathetic activity including bretylium, betanidine, guanethidine, debrisoquine, methyldopa, adrenergic neurone blockers and beta-blockers.

Cardiac glycosides: Increased risk of dysrhythmias.

Ergot alkaloids (ergotamine & methysergide): Increased risk of ergotism.

Oxytocin: Risk of hypertension.

Anaesthetic agents: Concurrent use with halogenated anaesthetic agents such as chloroform, cyclopropane, halothane, enflurane or isoflurane may provoke or worsen ventricular arrhythmias.

The use of drugs that induce hepatic microsomal enzymes, such as anticonvulsants and oral contraceptives, may increase the extent of metabolism of paracetamol, resulting in reduced plasma concentrations of the drug and a faster elimination rate.

The speed of absorption of paracetamol may be increased by metoclopramide or domperidone, and absorption reduced by cholestyramine.

The anticoagulant effect of warfarin and other coumarins may be enhanced by prolonged regular use of paracetamol with increased risk of bleeding; occasional doses have no significant effect.

Chronic alcohol intake can increase the hepatotoxicity of paracetamol overdose and may have contributed to the acute pancreatitis reported in one patient who had taken an overdose of paracetamol. Acute alcohol intake may diminish an individual's ability to metabolise large doses of paracetamol, the plasma half-life of which can be prolonged.

Caution should be taken when paracetamol is used concomitantly with flucloxacillin as concurrent intake has been associated with high anion gap metabolic acidosis due to pyroglutamic acidosis, especially in patients with risks factors (see section 4.4).

CNS depressants: Diphenhydramine may enhance the sedative effects of CNS depressants including barbiturates, hypnotics, opioid analgesics, anxiolytic sedatives, antipsychotics and alcohol.

Antimuscarinic drugs: Diphenhydramine may have additive muscarinic action with other drugs, such as atropine and tricyclic antidepressants. This may result in tachycardia, mouth dryness, gastrointestinal disturbances (e.g. colic), urinary retention and headache.

4.6. Fertility, pregnancy and lactation

Pregnancy

This medicine, like most medicines, should not be used during pregnancy unless the potential benefit of treatment to the mother outweighs any possible risk to the developing foetus.

Paracetamol, pseudoephedrine and diphenhydramine have been in widespread use for many years without any apparent ill consequence.

A large amount of data on pregnant women indicate neither malformative, nor feto/neonatal toxicity. Epidemiological studies on neurodevelopment in children exposed to paracetamol in utero show inconclusive results. If clinically needed, paracetamol can be used during pregnancy however it should be used at the lowest effective dose for the shortest possible time and at the lowest possible frequency.

The safety of pseudoephedrine in pregnancy has not been established.

Diphenhydramine is known to cross the placenta and, therefore, should only be used during pregnancy if considered essential by a doctor.

Breast-feeding

Pseudoephedrine is excreted in breast milk in small amounts, but the effect of this on breast-fed infants is not known. It has been estimated that approximately 0.4 to 0.7% of a single 60mg dose of pseudoephedrine ingested by a nursing mother will be excreted in the breast milk over 24 hours. Data from a study of lactating mothers taking 60 mg pseudoephedrine every 6 hours suggests that from 2.2 to 6.7% of the maximum daily dose (240 mg) may be available to the infant from a breastfeeding mother.

Paracetamol is excreted in breast milk, but not in a clinically significant amount. Available published data do not contra-indicate breast-feeding. A pharmacokinetic study of paracetamol in 12 nursing mothers revealed that less than 1% of a 650mg oral dose of paracetamol appeared in the breast-milk. Similar findings have been reported in other studies, therefore maternal ingestion of therapeutic doses of paracetamol does not appear to present a risk to the infant.

Diphenhydramine is excreted into human breast-milk, but levels have not been reported. Although the levels are not thought to be sufficiently high enough after therapeutic doses to affect the infant, the use of diphenhydramine during breast-feeding is not recommended.

4.7. Effects on ability to drive and use machines

May cause drowsiness. If affected, do not drive or operate machinery.

4.8. Undesirable effects

Adverse drug reactions (ADRs) identified during clinical trials and post-marketing experience with diphenhydramine, paracetamol, or pseudoephedrine (single ingredients) or combinations of diphenhydramine + paracetamol or pseudoephedrine + paracetamol, are listed below by System Organ Class (SOC).

The frequencies are defined according to the following convention:

Very common ≥1/10

Common ≥1/100 and < 1/10

Uncommon ≥1/1,000 and <1/100

Rare ≥1/10,000 and <1/1,000

Very rare <1/10,000

Not known (cannot be estimated from the available data)

ADRs are presented by frequency category based on 1) incidence in adequately designed clinical trials or epidemiology studies, if available, or 2) when incidence cannot be estimated, frequency category is listed as 'Not known'.

System Organ Class (SOC)

Frequency

Adverse Drug Reaction (Preferred Term)

Blood and lymphatic system disorders

Rare

Blood disorders, blood dyscrasias (including thrombocytopenia and agranulocytosis) have been reported following paracetamol use but were not necessarily causally related to the drug

Immune system disorder

Rare

Hypersensitivity (cross-sensitivity may occur with other sympathomimetics)

Psychiatric disorders

Common

Insomnia

Nervousness

Uncommon

Confusional state

Irritability

Rare

Depression

Sleep disorder

Not known

Anxiety

Euphoric mood

Excitability

Hallucinations

Paranoid delusions

Restlessness

Nervous system disorders

Very common

Headache

Somnolence

Sedation

Common

Dizziness

Paradoxical stimulation

Psychomotor impairment

Rare

Extrapyramidal disorder

Seizure

Tremor

Not known

Cerebrovascular accident

Paraesthesia

Posterior reversible encephalopathy syndrome (PRES) (see section 4.4)

Reversible cerebral vasoconstriction syndrome (RCVS) (see section 4.4)

Psychomotor hyperactivity

Eye disorders

Common

Vision blurred

Not known

Ischaemic optic neuropathy

Ear and labyrinth disorders

Uncommon

Tinnitus

Cardiac disorders

Rare

Palpitations

Not known

Dysrhythmias

Myocardial infarction/myocardial ischaemia

Tachycardia

Vascular disorders

Rare

Hypotension

Not known

Hypertension

Respiratory, thoracic and mediastinal disorders

Common

Increased viscosity of bronchial secretion

Not known

Dyspnoea

Nasal dryness

Gastrointestinal disorders

Common

Dry mouth

Gastrointestinal disorder

Nausea

Not known

Ischaemic colitis

Vomiting

Hepatobiliary disorders

Rare

Liver disorder

Skin and subcutaneous tissue disorders

Uncommon

Rash

Not known

Angioedema

Erythema

Fixed eruption

Pruritus

Rash pruritic

Serious skin reactions, including acute generalised exanthematous pustulosis (AGEP)

Urticaria

Renal and urinary disorders

Common

Urinary retention (in men in whom prostatic enlargement could have been an important predisposing factor)

Not known

Dysuria

General disorders and administration site conditions

Common

Asthenia

Not known

Chest discomfort

Metabolism and nutrition disorders

Not known

High anion gap metabolic acidosis

Very rare cases of serious skin reactions have been reported with paracetamol.

High anion gap metabolic acidosis

Cases of high anion gap metabolic acidosis due to pyroglutamic acidosis have been observed in patients with risk factors using paracetamol (see section 4.4).

Pyroglutamic acidosis may occur as a consequence of low glutathione levels in these patients.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorization of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

4.9. Overdose

Paracetamol:

Liver damage is possible in adults who have taken 10 g or more of paracetamol. Ingestion of 5 g or more of paracetamol may lead to liver damage if the patient has risk factors (see below).

Risk Factors:

If the patient

▪ Is on long term treatment with carbamazepine, phenobarbital, phenytoin, primidone, rifampicin, St John's Wort or other drugs that induce liver enzymes.

Or

▪ Regularly consumes ethanol in excess of recommended amounts.

Or

▪ Is likely to be glutathione deplete e.g. eating disorders, cystic fibrosis, HIV infection, starvation, cachexia.

Symptoms of paracetamol overdosage in the first 24 hours are pallor, nausea, vomiting, anorexia and abdominal pain. Liver damage may become apparent 12 to 48 hours after ingestion. Abnormalities of glucose metabolism and metabolic acidosis may occur. In severe poisoning, hepatic failure may progress to encephalopathy, haemorrhage, hypoglycaemia, cerebral oedema, and death.

Acute renal failure with acute tubular necrosis, strongly suggested by loin pain, haematuria and proteinuria, may develop even in the absence of severe liver damage. Cardiac arrhythmias and pancreatitis have been reported.

Haemolytic anaemia (in patients with glucose-6-phosphate dehydrogenase [G6PD] deficiency): Haemolysis has been reported in patients with G6PD deficiency, with use of paracetamol in overdose.

Management

Immediate treatment is essential in the management of paracetamol overdose. Despite a lack of significant early symptoms, patients should be referred to hospital urgently for immediate medical attention. Symptoms may be limited to nausea or vomiting and may not reflect the severity of overdose or the risk of organ damage. Management should be in accordance with established treatment guidelines, see BNF overdose section.

Treatment with activated charcoal should be considered if the overdose has been taken within 1 hour. Plasma paracetamol concentration should be measured at 4 hours or later after ingestion (earlier concentrations unreliable). Treatment with N-acetylcysteine may be used up to 24 hours after ingestion of paracetamol, however, the maximum protective effect is obtained up to 8 hours post-ingestion.

The effectiveness of the antidote declines sharply after this time. If required the patient should be given intravenous N-acetylcysteine, in line with the established dosage schedule. If vomiting is not a problem, oral methionine may be a suitable alternative for remote areas, outside hospital. Management of patients who present with serious hepatic dysfunction beyond 24h from ingestion should be discussed with the NPIS or a liver unit.

Pseudoephedrine:

Overdose may result in:

Hyperglycaemia, hypokalaemia, CNS stimulation, insomnia; irritability, restlessness, anxiety, agitation; confusion, delirium, hallucinations, psychoses, seizures, tremor, intracranial haemorrhage including intracerebral haemorrhage, drowsiness in children, mydriasis, palpitations, tachycardia, reflex bradycardia, supraventricular and ventricular arrhythmias, dysrhythmias, myocardial infarction, hypertension, vomiting, ischaemic bowel infarction, acute renal failure, difficulty in micturition.

Management

Necessary measures should be taken to maintain and support respiration and control convulsions. Catheterisation of the bladder may be necessary. If desired, the elimination of pseudoephedrine can be accelerated by acid diuresis or by dialysis.

Diphenhydramine:

Following overdose in adults, moderate symptoms have been associated with ingestions of greater than 300-500 mg and serious symptoms associated with doses greater than 1 g diphenhydramine.

Young children may be more sensitive to the effects of overdose.

Mild to moderate symptoms of overdose may include drowsiness, hyperpyrexia, anticholinergic effects (mydriasis, dry mouth and flushing), tachycardia, hypertension, nausea and vomiting. Agitation, confusion and hallucinations may develop with moderate poisoning. With higher doses, and particularly in children, symptoms of CNS excitation include insomnia, nervousness, tremors and epileptiform convulsions.

Severe symptoms may include delirium, psychosis, seizures, coma, hypotension, QRS widening, and ventricular dysrhythmias, including torsades de pointes, but are generally only reported in adults after large ingestions. Rhabdomyolysis and renal failure may rarely develop in patients with prolonged agitation, coma or seizures. Death may occur as a result of respiratory failure or circulatory collapse.

Management

Treatment of overdosage should be symptomatic and supportive. The benefit of gastric decontamination is uncertain. Consider activated charcoal (charcoal dose: 50 g for adults; 1 g/kg for children) only if the patient presents within 1 hour of ingestions of a potentially toxic amount. The intravenous use of physostigmine may be efficacious in antagonising severe anticholinergic symptoms.

💬 Ask about this leaflet

Ask anything about Benylin Day & Night Tablets. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.

Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.

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