How to use Alka-seltzer
Contents of the leaflet
- Leaflet attached to the packaging: patient information
- Alka-Seltzer, 324 mg, effervescent tablets
- What is Alka-Seltzer and what is it used for
- Important information before taking Alka-Seltzer
- How to take Alka-Seltzer
- Possible side effects
- How to store Alka-Seltzer
- Contents of the packaging and other information
Leaflet attached to the packaging: patient information
Alka-Seltzer, 324 mg, effervescent tablets
Acetylsalicylic acid
Read the leaflet carefully before taking the medicine, as it contains important information for the patient.
This medicine should always be used exactly as described in this patient leaflet or as directed by a doctor or pharmacist.
- The leaflet should be kept in case it needs to be read again.
- If advice or additional information is needed, a pharmacist should be consulted.
- If the patient experiences any side effects, including those not listed in this leaflet, they should inform their doctor or pharmacist. See section 4.
- If there is no improvement or the patient feels worse after 3-5 days, they should contact their doctor.
Table of contents of the leaflet:
- 1. What is Alka-Seltzer and what is it used for
- 2. Important information before taking Alka-Seltzer
- 3. How to take Alka-Seltzer
- 4. Possible side effects
- 5. How to store Alka-Seltzer
- 6. Contents of the packaging and other information
1. What is Alka-Seltzer and what is it used for
Acetylsalicylic acid, the active substance in Alka-Seltzer, has analgesic, anti-inflammatory, and antipyretic effects. Sodium citrate, which is formed after the tablet is dissolved in water, has buffering properties, which neutralizes excess stomach acid.
Indications:
- Mild to moderate pain, such as headaches, muscle aches (including general feeling of being unwell), toothaches
- Pain and fever in colds and flu
2. Important information before taking Alka-Seltzer
When not to take Alka-Seltzer
- in children under 12 years of age.
Warnings and precautions
Before starting Alka-Seltzer, the patient should discuss it with their doctor or pharmacist:
Acetylsalicylic acid should not be taken by women in the first and second trimester of pregnancy, unless absolutely necessary. Acetylsalicylic acid may cause bronchospasm and trigger asthma attacks or other hypersensitivity reactions. Patients with asthma, chronic respiratory diseases, hay fever, nasal polyps, and those who have allergic reactions to other substances (e.g., skin reactions, itching, hives) are particularly at risk. Patients undergoing surgery (including minor procedures, e.g., tooth extraction) should inform their doctor about taking Alka-Seltzer. Acetylsalicylic acid, even in small doses, reduces uric acid excretion from the body. In patients with a tendency to reduced uric acid excretion, the medicine may cause a gout attack. Medicines containing acetylsalicylic acid should not be given to children and adolescents during viral infections (with or without fever) without consulting a doctor. During some viral diseases, especially influenza A and B and chickenpox, there is a risk of developing Reye's syndrome - a rare but life-threatening disease that requires immediate medical attention. The risk of Reye's syndrome during viral infections may increase if acetylsalicylic acid is taken at the same time, although a causal relationship has not been proven. Persistent vomiting during an infection may indicate the onset of Reye's syndrome. Long-term use of medicines containing acetylsalicylic acid may cause headaches that worsen with each subsequent dose. Long-term use of painkillers, especially those containing multiple active substances, may lead to severe kidney function disorders and kidney failure.
Alka-Seltzer and other medicines
The patient should tell their doctor or pharmacist about all medicines they are currently taking or have recently taken, as well as any medicines they plan to take. Special caution should be exercised when taking Alka-Seltzer with the following medicines, as acetylsalicylic acid enhances:
- the toxic effects of methotrexate on the bone marrow; acetylsalicylic acid should not be taken at the same time as methotrexate at doses of 15 mg per week or higher; concurrent use of methotrexate at doses less than 15 mg per week requires special caution;
concurrent use of methotrexate at doses less than 15 mg per week requires special caution;
- the effects of anticoagulant, thrombolytic (dissolving blood clots), and antiplatelet medications, which may increase the risk of prolonged bleeding time and bleeding;
- the risk of stomach ulcers and gastrointestinal bleeding if taken concurrently with corticosteroids, other non-steroidal anti-inflammatory drugs, including other salicylates, or if alcohol is consumed during treatment; after stopping systemic corticosteroid therapy (except for hydrocortisone used as replacement therapy in Addison's disease), the risk of salicylate overdose increases;
- the effects of digoxin (a heart medication), as it increases its concentration in the blood;
- the effects of antidiabetic medications, such as insulin and sulfonylurea derivatives;
- the toxic effects of valproic acid (a medication used in epilepsy), which in turn enhances the antiplatelet effect of acetylsalicylic acid;
- the effects of selective serotonin reuptake inhibitors (antidepressants).
Special caution should be exercised when taking Alka-Seltzer with the following medicines, as acetylsalicylic acid weakens:
- the effects of uricosuric medications (used to treat gout) that increase uric acid excretion from the body (e.g., benzbromarone, probenecid), which may worsen gout symptoms;
- the effects of diuretics;
- the effects of certain antihypertensive medications (from the group of so-called angiotensin-converting enzyme inhibitors).
Alka-Seltzer can be taken with the above-mentioned medicines (except for methotrexate at doses of 15 mg per week or higher) only after consulting a doctor.
Alka-Seltzer with food, drink, or alcohol
See section 3 of the leaflet. Note: Alcohol may increase the risk of gastrointestinal side effects, such as stomach ulcers or bleeding.
Pregnancy, breastfeeding, and fertility
In pregnancy, breastfeeding, or if pregnancy is suspected, or if the patient is planning to become pregnant, they should consult their doctor or pharmacist before taking the medicine. Pregnancy
Alka-Seltzer should not be taken during the last 3 months of pregnancy, as it may harm the unborn child or cause complications during delivery. The medicine may cause kidney and heart function disorders in the unborn child. It may also affect the patient's and child's tendency to bleed and cause delayed or prolonged delivery. Alka-Seltzer should not be taken during the first 6 months of pregnancy, unless absolutely necessary and recommended by a doctor. If the patient requires treatment during this period or is trying to become pregnant, they should use the smallest possible dose for the shortest possible time. If Alka-Seltzer is taken for more than a few days from the 20th week of pregnancy, it may cause kidney function disorders in the unborn child, leading to reduced amniotic fluid (oligohydramnios) or narrowing of the blood vessel (ductus arteriosus) in the child's heart. If treatment is necessary for more than a few days, the doctor may recommend additional monitoring.
Breastfeeding
Acetylsalicylic acid passes into breast milk in small amounts.
Fertility
Alka-Seltzer belongs to a group of medicines that may adversely affect female fertility. This effect is temporary and disappears after the end of therapy.
Driving and using machines
The medicine does not affect the ability to drive or use machines.
Alka-Seltzer contains sodium, benzyl alcohol, and glucose (a component of maltodextrin with flavorings)
One Alka-Seltzer tablet contains 477 mg of sodium (the main component of common salt). This corresponds to 24% of the maximum recommended daily sodium intake in the diet for adults. The maximum daily dose of this product is equivalent to 288% of the WHO-recommended maximum daily sodium intake. Benzyl alcohol may cause allergic reactions. If the patient has previously been diagnosed with intolerance to some sugars, they should consult their doctor before taking the medicine.
3. How to take Alka-Seltzer
This medicine should always be used exactly as described in the patient leaflet or as directed by a doctor or pharmacist. In case of doubts, the patient should consult their doctor or pharmacist.
The recommended dose of Alka-Seltzer is:
Adults:
1 to 3 effervescent tablets (i.e., 324 to 972 mg of acetylsalicylic acid) at a time. If necessary, the single dose may be repeated after at least 4 to 6 hours. No more than 4000 mg of acetylsalicylic acid (i.e., a maximum of 12 effervescent tablets per day) should be taken in 24 hours.
Children over 12 years of age:
The medicine may be used in children over 12 years of age only on the advice of a doctor.
The patient should take 1 effervescent tablet (i.e., 324 mg of acetylsalicylic acid) at a time. If necessary, the single dose may be repeated up to 3 times a day, but no more than every 4-6 hours. No more than 3 effervescent tablets (i.e., 972 mg of acetylsalicylic acid) should be taken per day.
The medicine should be used with caution in patients with impaired liver and/or kidney function.
The medicine should not be taken for more than 3-5 days without consulting a doctor.
The tablets should be dissolved in a glass of water and the effervescent liquid should be drunk. The medicine should be taken after meals.
Taking a higher dose of Alka-Seltzer than recommended
Acetylsalicylic acid poisoning can occur due to prolonged use of the medicine (mild poisoning) or overdose (severe poisoning), which can be life-threatening, e.g., after accidental ingestion by children or the elderly. Symptoms of mild poisoning include: dizziness (including vertigo), tinnitus, hearing loss, excessive sweating, nausea, and vomiting, headache, confusion (disorders of consciousness with disorientation, thinking, and speech disorders, delusions, hallucinations, anxiety, and psychomotor agitation), rapid breathing, deep breathing, and symptoms of respiratory alkalosis (spots before the eyes, fainting). In the case of severe poisoning, the following may also occur: high fever, respiratory disorders (up to respiratory arrest and suffocation), heart and blood vessel disorders (from irregular heartbeat, low blood pressure to cardiac arrest), fluid and electrolyte loss (from dehydration, oliguria [reduced urine output below 400-500 ml per day in adults] to kidney failure), increased or decreased blood glucose levels (especially in children), ketoacidosis, gastrointestinal bleeding, blood coagulation disorders, neurological disorders manifesting as lethargy, confusion, and up to coma and convulsions. In case of taking a higher dose of the medicine than recommended, the patient should immediately consult a doctor or pharmacist, and in case of severe poisoning, the patient should be taken to the hospital immediately. Treatment of poisoning involves gastric lavage, administration of activated charcoal, and use of alkaline diuresis. In severe cases, forced alkaline diuresis, peritoneal dialysis, or hemodialysis may be necessary.
Missing a dose of Alka-Seltzer
In case of missing a dose and persistence of symptoms, the patient should take the next dose of Alka-Seltzer. A double dose should not be taken to make up for the missed dose.
Stopping Alka-Seltzer treatment
In case of any further doubts about the use of this medicine, the patient should consult their doctor or pharmacist.
4. Possible side effects
Like all medicines, Alka-Seltzer can cause side effects, although not everybody gets them.
Note:
- If vomiting with blood or black, tarry stools occurs, the patient should stop taking the medicine and consult their doctor.
- A symptom of a severe hypersensitivity reaction may be: swelling of the face and eyelids, swelling of the tongue and larynx with narrowing of the airways, difficulty breathing, shortness of breath up to asthma attacks, rapid heartbeat, sudden drop in blood pressure up to life-threatening shock. If any of these symptoms occur, the patient should immediately seek medical attention. These reactions can occur even after the first dose of the medicine.
The frequency of possible side effects listed below is defined as: frequent (more than 1 in 100 but less than 1 in 10), rare (more than 1 in 10,000 but less than 1 in 1,000), very rare (less than 1 in 10,000), unknown (frequency cannot be estimated from available data).
Gastrointestinal disorders:
Frequent:
Stomach and abdominal pain, heartburn, indigestion.
Rare:
Gastrointestinal inflammation, potentially life-threatening gastrointestinal bleeding: overt (vomiting with blood, black stools) or occult (more frequent with higher doses); stomach or duodenal ulcers, perforation.
Unknown: Enteropathy (especially during long-term use), nausea, vomiting.
Liver and bile duct disorders:
Very rare:
Transient liver function disorders (increased aminotransferase activity).
Nervous system disorders:
Rare:
Brain hemorrhage (especially in patients with uncontrolled hypertension and/or concurrent use of other anticoagulant medications) potentially life-threatening.
Unknown:
Dizziness usually being symptoms of overdose.
Ear and labyrinth disorders:
Frequent:
Tinnitus usually being symptoms of overdose.
Blood and lymphatic system disorders:
Unknown:
Increased risk of bleeding, prolonged bleeding time, prothrombin time, thrombocytopenia. The consequence of bleeding may be the development of iron deficiency anemia or bleeding anemia, manifesting as weakness, pallor, hypoperfusion, as well as abnormal laboratory test results. Hemolysis and hemolytic anemia in patients with severe glucose-6-phosphate dehydrogenase deficiency.
Vascular disorders:
Unknown:
Bleeding (postoperative, nasal, gingival, genitourinary), hematoma.
Renal and urinary disorders:
Unknown:
Renal function disorders and severe kidney damage.
Immune system disorders:
Rare:
Hypersensitivity reactions with clinical symptoms and abnormal laboratory test results, such as: mild to moderate reactions involving the skin, respiratory system, cardiovascular system with symptoms such as: rash, urticaria, edema (including angioedema), rhinitis, nasal congestion.
Unknown:
Severe reactions, including anaphylactic shock, respiratory and cardiac disorders.
Respiratory, thoracic, and mediastinal disorders:
Unknown:
Respiratory disease, which worsens after taking acetylsalicylic acid.
Reporting side effects
If any side effects occur, including those not listed in this leaflet, the patient should inform their doctor, pharmacist, or nurse. Side effects can be reported directly to the Department of Drug Safety Monitoring of the Office for Registration of Medicinal Products, Medical Devices, and Biocidal Products: Al. Jerozolimskie 181C, 02-222 Warsaw, phone: 22 49-21-30, fax: 22 49-21-309, website: https://smz.ezdrowie.gov.pl. Side effects can also be reported to the marketing authorization holder. By reporting side effects, more information can be collected on the safety of the medicine.
5. How to store Alka-Seltzer
Store at a temperature below 25°C.
The medicine should be stored out of sight and reach of children.
Do not use this medicine after the expiry date stated on the carton after the abbreviation "EXP".
The expiry date refers to the last day of the month.
Medicines should not be disposed of via wastewater or household waste. The patient should ask their pharmacist how to dispose of medicines that are no longer needed. This will help protect the environment.
6. Contents of the packaging and other information
What Alka-Seltzer contains
The active substance of Alka-Seltzer is acetylsalicylic acid (Acidum acetylsalicylicum).
The other ingredients of the medicine are: citric acid, sodium bicarbonate, Povidone 25, a mixture of dimeticone and calcium silicate (70%: 30%), a mixture of sodium benzoate and sodium saccharin (85%: 15%), sodium citrate, lemon flavor (including maltodextrin, butylhydroxyanisole E320, butylhydroxytoluene E321, benzyl alcohol), lime flavor (including maltodextrin, benzyl alcohol, α-tocopherol E307).
What Alka-Seltzer looks like and what the pack contains
One double sachet contains 2 effervescent tablets.
A cardboard box contains 6, 10, or 40 effervescent tablets in the form of 3, 5, or 20 double sachets, each containing 2 effervescent tablets.
Packaging containing 2 effervescent tablets (1 double sachet) is also authorized.
Marketing authorization holder
Bayer Sp. z o.o.
Aleje Jerozolimskie 158
02-326 Warsaw
Phone: 22 572 35 00
Fax: 22 572 35 55
Manufacturer
Bayer Bitterfeld GmbH
OT Greppin
Salegaster Chaussee 1
06803 Bitterfeld-Wolfen
Germany
Date of last revision of the leaflet: December 2023

- Country of registration
- Dosage formTablets, 324 mg
- ATC codeN02BA01
- Active substance
- Prescription requiredNo
- Manufacturer
- ImporterBayer Bitterfeld GmbH Pharma Innovations Sp. z o.o.
- This information is for reference only and does not constitute medical advice. Always consult a doctor before taking any medication. Oladoctor is not responsible for medical decisions based on this content.
- Alternatives to Alka-seltzerDosage form: Tablets, 324 mgActive substance: acetylsalicylic acidPrescription not requiredDosage form: Tablets, 324 mgActive substance: acetylsalicylic acidPrescription not requiredDosage form: Tablets, 324 mgActive substance: acetylsalicylic acidPrescription not required
Online doctors for Alka-seltzer
Discuss questions about Alka-seltzer, including use, safety considerations and prescription review, subject to medical assessment and local regulations.
Get Alka-seltzer Prescription Online
Fill in a 2-min form
Tell us your symptoms, history, and what medicine you're requesting.
Pick a doctor or let us assign
Choose a specialist or we'll match you with the next available doctor.
Doctor reviews your case
Usually within 30 minutes. They may ask follow-up questions via chat.
Collect from any pharmacy
Electronic prescription sent to your email — valid across Spain.
Frequently Asked Questions
Alka-seltzer does not require a prescription in Poland. You can check with a doctor online whether this medicine may be appropriate for your situation.
The active ingredient in Alka-seltzer is acetylsalicylic acid. This information helps identify medicines with the same composition but different brand names.
Alka-seltzer is manufactured by Bayer Bitterfeld GmbH Pharma Innovations Sp. z o.o.. Pharmacy brands and packaging may differ depending on the distributor.
Doctors such as Family doctors, Psychiatrists, Dermatologists, Cardiologists, Endocrinologists, Gastroenterologists, Pulmonologists, Nephrologists, Rheumatologists, Hematologists, Infectious disease physicians, Allergists, Geriatricians, Paediatricians, Oncologists may assess whether Alka-seltzer is appropriate, depending on your situation and local regulations. You can book an online consultation to discuss your symptoms and possible next steps.
Spain has a well-developed healthcare infrastructure across major cities such as Madrid, Barcelona, Valencia, and Seville. Pharmacies are widely available and operate under strict regulations, ensuring access to prescribed medications.
You can buy Alka-seltzer in Madrid, Barcelona, Seville, or Valencia at any local pharmacy with a valid prescription.
To obtain a prescription, you can use Oladoctor:
Other medicines with the same active substance (acetylsalicylic acid) include Alka-seltzer, Alka-seltzer, Alka-seltzer. These may have different brand names or formulations but contain the same therapeutic ingredient. Always consult a doctor before switching or starting a new medicine.
















