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Alka-Seltzer XS

Active Ingredient:
acetylsalicylic acid, caffeine, paracetamol
About Medicine
{healthcare_pro_orange} This information is for use by healthcare professionals
Last updated on emc: 15 Jun 2023
1. Name of the medicinal product

Alka-Seltzer XS

2. Qualitative and quantitative composition

Each tablet contains acetylsalicylic acid (aspirin) 267 mg, paracetamol 133 mg and caffeine 40 mg.

For the full list of excipients, see section 6.1.

3. Pharmaceutical form

Effervescent tablets.

4. Clinical particulars
4.1 Therapeutic indications

For rapid relief of pain including migraine, headache, period pains, neuralgia, toothache, sore throat.

Symptomatic relief of rheumatic pain, sciatica, lumbago, fibrositis, muscular aches and pains.

Symptomatic relief of influenza, feverishness, feverish colds.

4.2 Posology and method of administration

Alka-Seltzer XS is for oral ingestion after dissolution in water. It dissolves more quickly in warm water.

Adults: Two tablets in water. This dose may be repeated every four hours up to four doses in 24 hours but the dosage should not be continued for more than three days without consulting a doctor. Do not exceed the stated dose.

Do not give to children under 16 years, unless specifically indicated (e.g. for Kawasaki's disease).

4.3 Contraindications

Alka-Seltzer XS should not be administered to patients:

with known hypersensitivity reactions (e.g. bronchospasm, rhinitis, urticaria) in response to acetylsalicylic acid, other salicylates, or substances with similar actions e.g. non-steroidal anti-inflammatory drugs.

with known hypersensitivity to paracetamol or any of the other ingredients, refer to section 2.

with active peptic ulceration or a history of peptic ulceration.

with haemorrhagic diseases such as haemophilia.

in the last trimester of pregnancy (see sections 4.4 and 4.6).

receiving doses of methotrexate at 15mg/week or greater (see section 4.5).

4.4 Special warnings and precautions for use

Acetylsalicylic acid may precipitate bronchospasm and induce asthma attacks or other hypersensitivity reactions in susceptible individuals.

Caution should be exercised in patients:

• with a history of gastrointestinal disorders

• in the first or second trimester of pregnancy or who are breast-feeding (see sections 4.3 and 4.6)

• taking anticoagulants (e.g. coumarin derivatives or heparin)

• whose renal or hepatic function is impaired. The hazards of overdose are greater in those with non-cirrhotic alcoholic liver disease.

Aspirin can cause gout in patients with low uric acid excretion.

Alka-Seltzer XS contains paracetamol and so other paracetamol-containing preparations should be avoided. The maximum dose of paracetamol for adults is 4g daily.

Do not exceed the recommended dose. If symptoms persist consult your doctor. Keep out of the reach of children.

There is a possible association between aspirin and Reye's syndrome when given to children. Reye's syndrome is a very rare disease, which affects the brain and liver, and can be fatal. For this reason aspirin should not be given to children aged under 16 years unless specifically indicated (e.g. Kawasaki's disease).

Due to its inhibitory effect on platelet aggregation aspirin may cause increased bleeding during and after surgery.

Leaflet warning: 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.

Label warning: Do not take anything else containing paracetamol while taking this medicine. Talk to a doctor at once if you take too much of this medicine, even if you feel well.

This medicinal product contains 472 mg sodium per tablet, equivalent to 23.6% of the WHO recommended maximum daily intake of 2 g sodium for an adult.

4.5 Interaction with other medicinal products and other forms of interaction

Alka-Seltzer XS may:

Enhance the activity of anticoagulants such as warfarin and other coumarins.

Enhance the activity of insulin and sulphonylurea hypoglycaemic agents.

Enhance the activity of methotrexate and increase its toxicity (see section 4.3).

Diminish the effects of uricosuric agents.

Diminish the effects of diuretics.

Potentiate the risk of gastro-intestinal bleeding during concomitant therapy with corticosteroids.

Potentiate the effects and side-effects of other non-steroidal anti-inflammatory drugs.

Enhance the plasma concentrations of digoxin.

Enhance the effects of some anti-epileptics, such as sodium valproate and phenytoin.

Interact with antihyperstensive medicines.

Increase risk of bleeding with thrombolytics and other anti-platelet agents e.g. ticlopidine.

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

Decreased blood salicylate levels may occur when aspirin is taken concomitantly with glucocorticoids. There is a risk of salicylate overdose when glucocorticoids treatment is stopped.

At doses of 3g/day or more, aspirin may:

Increase risk of ulcers and gastro-intestinal bleeding when taken with other NSAIDs.

Decrease glomerular filtration when taken with diuretics.

Decrease glomerular filtration and anti-hypertensive effect when taken with ACE inhibitors.

When taken with alcohol, the effects of acetylsalicylic acid on the gastro- intestinal tract may increase.

4.6 Fertility, pregnancy and lactation

Alka-Seltzer XS should not be taken by pregnant or nursing women unless directed by a doctor.


Acetylsalicylic acid:

Although clinical and epidemiological evidence suggests the safety of acetylsalicylic acid for use in pregnancy, caution should be exercised when administered to pregnant patients.

Acetylsalicylic acid has the ability to alter platelet function and, therefore, there may be a risk of haemorrhage in infants whose mothers have consumed acetylsalicylic acid during pregnancy. The onset of labour may be delayed and the duration increased, with an increase in maternal blood loss. Therefore, analgesic doses should be avoided during the last trimester of pregnancy.

High doses of acetylsalicylic acid may result in closure of foetal ductus arteriosus in utero and possibly persistent pulmonary hypertension in the new born. Kernicterus may be a consequence of jaundice in neonates.

Administration of aspirin at doses greater than 300mg/day, shortly before birth can lead to intra-cranial haemorrhages, particularly in premature babies.


Epidemiological studies in human pregnancy have shown no ill effects due to paracetamol used in the recommended dosage. Epidemiological studies on neurodevelopment in children exposed to paracetamol in utero show inconclusive results. If clinically needed, patients should follow the advice of their doctor regarding its use.


Acetylsalicylic acid:

The intake of acetylsalicylic acid by breast-feeding patients should be avoided as there is a risk of Reye's syndrome. Regular use of high doses could impair platelet function and produce hypoprothrombinaemia in the infant if neonatal vitamin K stores are low.

When aspirin has been taken regularly or high doses have been taken then breast-feeding should be discontinued early.


Paracetamol is excreted in breast milk but not in a clinically significant amount. Available published data on paracetamol does not contraindicate it for breast feeding.

4.7 Effects on ability to drive and use machines


4.8 Undesirable effects

Acetylsalicylic acid:

Gastrointestinal disorders have been reported for acetylsalicylic acid containing products e.g. nausea, diarrhoea, vomiting and gastro-intestinal bleeding which can lead to anaemia in some cases. Gastrointestinal ulcers may develop, which may lead to haemorrhaging and perforation.

Rare cases of bronchospasm, asthmatic or hypersensitivity reactions have been reported for acetylsalicylic acid containing products.

Isolated cases of liver function disturbances and severe skin reactions have also been reported.

Due to the effect on platelet aggregation, acetylsalicylic acid may be associated with an increased risk of bleeding.

Dizziness and tinnitus have also been reported for acetylsalicylic acid but these side effects are more commonly indicative of an overdose.


Adverse effects of paracetamol are rare but hypersensitivity including skin rash may occur.

Very rare cases of serious skin reactions have been reported.

There have been reports of blood dyscrasis including thrombocytopenia and agranulocytosis, but these were not necessarily causally related to paracetamol.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation 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:

4.9 Overdose


Liver damage is possible in adults who have taken 10g or more of paracetamol.


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, coma and death. Acute renal failure with acute tubular necrosis may develop even in the absence of severe liver damage. Cardiac arrhythmias and pancreatitis have been reported.


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 and any patient who had ingested around 7.5g or more of paracetamol in the preceding 4 hours should undergo gastric lavage. Administration of oral methionine or intravenous N- acetylcysteine which may have a beneficial effect up to at least 48 hours after the overdose, may be required. General supportive measures must be available.

Acetysalicyclic acid

Salicylate poisoning is usually associated with plasma concentrations >350 mg/L (2.5 mmol/L). Most adult deaths occur in patients whose concentrations exceed 700 mg/L (5.1 mmol/L). Single doses less than 100 mg/kg are unlikely to cause serious poisoning.


Common features include vomiting, dehydration, tinnitus, vertigo, deafness, sweating, warm extremities with bounding pulses, increased respiratory rate and hyperventilation. Some degree of acid-base disturbance is present in most cases.

A mixed respiratory alkalosis and metabolic acidosis with normal or high arterial pH (normal or reduced hydrogen ion concentration) is usual in adults and children over the age of four years. In children aged four years or less, a dominant metabolic acidosis with low arterial pH (raised hydrogen ion concentration) is common. Acidosis may increase salicylate transfer across the blood brain barrier.

Uncommon features include haematemesis, hyperpyrexia, hypoglycaemia, hypokalaemia, thrombocytopaenia, increased INR/PTR, intravascular coagulation, renal failure and non-cardiac pulmonary oedema.

Central nervous system features including confusion, disorientation, coma and convulsions are less common in adults than in children.


Give activated charcoal if an adult presents within one hour of ingestion of more than 250 mg/kg. The plasma salicylate concentration should be measured, although the severity of poisoning cannot be determined from this alone and the clinical and biochemical features must be taken into account. Elimination is increased by urinary alkalinisation, which is achieved by the administration of 1.26% sodium bicarbonate. The urine pH should be monitored. Correct metabolic acidosis with intravenous 8.4% sodium bicarbonate (first check serum potassium).

Forced diuresis should not be used since it does not enhance salicylate excretion and may cause pulmonary oedema.

Haemodialysis is the treatment of choice for severe poisoning and should be considered in patients with plasma salicylate concentrations >700 mg/L (5.1 mmol/L), or lower concentrations associated with severe clinical or metabolic features. Patients under ten years or over 70 have increased risk of salicylate toxicity and may require dialysis at an earlier stage.

5. Pharmacological properties
5.1 Pharmacodynamic properties

The therapeutic uses of Alka-Seltzer XS are based on the following pharmacological properties of the active ingredients:




- analgesic, antipyretic and anti-inflammatory.

- analgesic, antipyretic.

- central nervous system stimulant.

The buffer converts acetylsalicylic acid to sodium acetylsalicylate and promotes gastric emptying.

5.2 Pharmacokinetic properties

Acetylsalicylate is rapidly absorbed from the small intestine after oral ingestion of Alka-Seltzer XS and rapidly distributed to all body tissues.

Acetylsalicylate is hydrolysed to its active primary metabolite salicylic acid and completely excreted in the urine, principally as glucoronic acid and glycine conjugates of salicylic acid, but also as salicylic acid itself. Salicylates are extensively bound to plasma proteins. Peak plasma levels occur at approximately 20 minutes. Following administration of acetylsalicylic acid, salicylic acid can be detected in breast milk, cerebral spinal fluid and synovial fluid. The substance crosses the placenta.

Paracetamol is rapidly absorbed from the upper gastrointestinal tract after oral administration of Alka-Seltzer XS, with the small intestine being an important site of absorption. Peak plasma concentration occurs about 30 minutes to 2 hours after ingestion. It is rapidly distributed throughout the body and is primarily metabolised in the liver with excretion via the kidney. Elimination half-life varies from about 1 to 4 hours. Paracetamol crosses the placental barrier and is present in breast milk.

Caffeine is readily absorbed after oral administration and passes readily into the central nervous system. Excretion is renal.

5.3 Preclinical safety data


Conventional studies using the currently accepted standards for the evaluation of toxicity to reproduction and development are not available.

6. Pharmaceutical particulars
6.1 List of excipients

Citric Acid

Sodium Hydrogen Carbonate

6.2 Incompatibilities

None known.

6.3 Shelf life

30 months.

6.4 Special precautions for storage

Laminated paper/polyethylene/aluminium surlyn heat sealed foil : Do not store above 25° C. Store in the original package.

Laminated aluminium/polyethylene surlyn heat sealed foil: Do not store above 25° C. Store in the original package.

6.5 Nature and contents of container

Laminated paper/polyethylene/aluminium surlyn heat sealed foil, or laminated aluminium/polyethylene surlyn heat sealed foil.

Aluminium foil pouches containing one or two tablets. Pack sizes available are 2, 10, 12, 20, and 30 tablets.

6.6 Special precautions for disposal and other handling

None applicable.

7. Marketing authorisation holder

Bayer plc

400 South Oak Way



8. Marketing authorisation number(s)

PL 00010/0510

9. Date of first authorisation/renewal of the authorisation

Date of first authorisation: 21st June 2006

Date of last renewal:

10. Date of revision of the text


Bayer plc
Company image
400 South Oak Way, Reading, Berkshire, RG2 6AD
+44 (0)118 206 3000
Medical Information e-mail
[email protected]