Alka-seltzer wake-up call

Overdose

Aspirin overdose:

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.

Symptoms:

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.

Management:

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 alone 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 10 years or over 70 have increased risk of salicylate toxicity and may require dialysis at an earlier stage.

Caffeine overdose:

Symptoms: Common features include GI disturbance, epigastric pain, vomiting, diuresis, tachycardia or cardiac arrhythmia, “rambling” flow of thought and speech, psychomotor agitation, CNS stimulation (insomnia, restlessness, excitement, agitation, jitteriness, tremors and convulsions) or periods of inexhaustibility.

Management:

No specific antidote is available, but supportive measures such as beta adrenoceptor antagonists to reverse the cardiotoxic effects may be used.

Contraindications

Hypersensitivity to aspirin, other salicylates, caffeine or any of the excipients. A history of hypersensitivity reactions (e.g. asthma, bronchospasm, rhinitis, urticaria, nasal polyps) in response to aspirin or non-steroidal anti- inflammatory drugs.

Hypersensitivity to peanut or soya.

Patients with severe hepatic or renal failure. Aspirin is known to cause sodium and water retention which may exacerbate hypertension, congestive heart failure and renal impairment.

Patients with active peptic ulceration or a history of peptic ulceration. History of gastrointestinal bleeding or perforation after treatment with aspirin or other NSAIDS.

A history of haemophilia, hypothrombinaemia or other clotting disorders. A history of gout.

Incompatibilities

Iron salts, phenobarbital sodium, hexamine, quinine salts, potassium and sodium iodides, free acids, alkali hydroxides, carbonates and stearates.

Undesirable effects

Adverse events from historical clinical trial data are both infrequent and from small patient exposure. Events reported from extensive post-marketing experience at therapeutic/labelled dose and considered attributable are tabulated below by MedDRA System Organ Class. Due to limited clinical trial data, the frequency of these adverse events is not known (cannot be estimated from available data).

Aspirin

Body System

Undesirable effect

Gastrointestinal disorders

Nausea, vomiting, dyspepsia. Gastrointestinal ulceration, gastrointestinal haemorrhage and gastritis.

Renal and urinary disorders

Renal dysfunction, increased blood uric acid levels.

Hepatobiliary disorders

Elevation in aminotransferase levels.

Blood and lymphatic system disorders

Prolonged bleeding time.

Thrombocytopenia.

Ecchymosis

Metabolism and Nutrition disorders

Sodium and fluid retention.

Immune system disorders

Hypersensitivity reactions e.g. rhinitis, angioedema, urticaria, bronchospasm, skin reactions and anaphylaxis.

Respiratory, thoracic and mediastinal disorders

Bronchospasm in patients sensitive to aspirin and other NSAIDs

Ear and labyrinth disorders

Tinnitus, temporary hearing loss.

Caffeine

Body System

Undesirable effect

Central nervous system

Nervousness and dizziness.

When the recommended aspirin-caffeine dosing regimen is combined with dietary caffeine intake, the resulting higher dose of caffeine may increase the potential for caffeine- related adverse effects such as insomnia, restlessness, anxiety, irritability, headaches, gastrointestinal disturbances and palpitations.

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:www.mhra.gov.uk/yellowcard.

Preclinical safety data

None stated

Therapeutic indications

The product may be recommended as an analgesic and antipyretic for:

a) The symptomatic relief of influenza, feverishness, chills and colds, including feverish colds.

b) The relief of mild to moderate pain including headache, migraine, neuralgia, toothache, sore throat, period pains, aches and pains, rheumatic pain and muscular aches and pains.

Pharmacodynamic properties

Aspirin provides the analgesic and antipyretic actions required for the recommended indications.

Caffeine is a mild stimulant.

Pharmacokinetic properties

Aspirin is rapidly absorbed from the upper gastrointestinal tract after oral administration and is rapidly distributed throughout the whole body. It is hydrolysed to its active primary metabolite salicylic acid and completely excreted in the urine, principally as glucuronic acid and glycine conjugates of salicylic acid, but also as salicylic acid itself.

Salicylates are extensively bound to plasma proteins. Maximum plasma concentrations are reached after 10-40 minutes (acetylsalicylic acid) and 0.3 - 2 hours (total salicylate) depending on dosage form. The elimination half life of acetylsalicylic acid is dose-dependent, typically two hours after a single dose of 0.5 g aspirin, 4 hours after 1 gram and 20 hours after 5 grams.

Following administration of acetylsalicylic acid, salicylic acid can be detected in breast milk, cerebral spinal fluid and synovial fluid. The substance crosses the placenta.

Name of the medicinal product

Alka-Seltzer Wake-Up Call

Qualitative and quantitative composition

Acetylsalicylic Acid; Caffeine

Special warnings and precautions for use

Aspirin should be used with caution in patients with hypertension, mild to moderate renal or hepatic impairment, or in patients who are dehydrated. Aspirin decreases platelet adhesiveness and increases bleeding time.

Haematological and haemorrhagic effects can occur, and may be severe. Patients should report any unusual bleeding symptoms to their physician. Due to its inhibitory effect on platelet aggregation aspirin may cause increased bleeding during and after surgery.

Aspirin may precipitate acute haemolytic anaemia in patients with G6PDH deficiency.

Excessive intake of caffeine (e.g. coffee, tea and some canned drinks) should be avoided while taking this product.

Lactose: Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.

If symptoms persist consult your doctor.

Contains aspirin.

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. for Kawasaki's disease).

If you suffer from asthma, allergic disease, kidney or liver problems consult your doctor before taking this product.

Effects on ability to drive and use machines

None

Dosage (Posology) and method of administration

Directions for use: Mix the powder with a little water and stir before drinking.

Adults and children aged 16 years and over:

One powder to be taken every three to four hours as required. Do not exceed six powders in any period of 24 hours.

Elderly: Use with particular caution in elderly patients who are more prone to adverse events.

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

Product should be discontinued if pain gets worse or lasts more than 10 days (or lasts more than 3 days for fever).

Special precautions for disposal and other handling

Not applicable.