How to use Alka-seltzer
Contents of the leaflet
- Leaflet attached to the packaging: patient information
- Warning! The leaflet should be kept. Information on the immediate packaging in a foreign language.
- 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
- Package contents and other information
Leaflet attached to the packaging: patient information
Warning! The leaflet should be kept. Information on the immediate packaging in a foreign language.
Alka-Seltzer
324 mg, effervescent tablets
Acetylsalicylic acid
Alka-Seltzer and Алка-Зелцер are trade names of the same medicine written in Polish and Bulgarian.
It is necessary to carefully read the contents of the leaflet 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 any side effects not listed in this leaflet, they should inform their doctor, pharmacist, or nurse. See section 4.
- If there is no improvement after 3-5 days or the patient feels worse, 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. Package contents 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 the course of a cold or flu
2. Important information before taking Alka-Seltzer
When not to take Alka-Seltzer
- if the patient is allergic to the active substance - acetylsalicylic acid, other salicylates, or any of the other ingredients of this medicine (listed in section 6),
- if the patient has a bleeding disorder,
- if the patient has acute stomach or duodenal ulcer,
- if the patient has severe heart failure or severe liver or kidney failure,
- if the patient has ever had asthma attacks, caused by the administration of salicylates or substances with similar effects, especially non-steroidal anti-inflammatory drugs,
- if the patient is taking methotrexate (used in cancer treatment) at doses of 15 mg per week or higher,
- if the patient is in the last trimester of pregnancy,
- in children under 12 years of age.
Warnings and precautions
Before starting to take Alka-Seltzer, the patient should discuss it with their doctor or pharmacist:
- if the patient is hypersensitive to non-steroidal anti-inflammatory and anti-rheumatic drugs or other allergenic substances,
- if the patient is taking anticoagulant drugs,
- if the patient has impaired liver function,
- if the patient has impaired kidney function or circulatory disorders (e.g., kidney vessel disease, congestive heart failure, reduced blood volume, extensive surgery, sepsis, severe bleeding), as acetylsalicylic acid may further increase the risk of kidney function disorders and severe kidney failure,
- if the patient has had a history of (chronic or recurrent) stomach ulcers or gastrointestinal bleeding,
- if the patient has a genetic disorder characterized by a deficiency of the enzyme - glucose-6-phosphate dehydrogenase, as the administration of acetylsalicylic acid may cause hemolysis or hemolytic anemia,
- if the patient is breastfeeding.
Drugs containing acetylsalicylic acid should not be taken by women in the first and second trimester of pregnancy, unless it is 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 patients who experience allergic reactions to other substances (e.g., skin reactions, itching, hives) are particularly at risk of such reactions.
Patients undergoing surgical procedures (including minor procedures, e.g., tooth extraction) should inform their doctor about taking Alka-Seltzer.
Acetylsalicylic acid, even in small doses, reduces the excretion of uric acid from the body. In patients with a tendency to reduced uric acid excretion, the drug may cause a gout attack.
Drugs 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 in the case of influenza A and B virus infection 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 developing Reye's syndrome during viral infections may increase if acetylsalicylic acid is administered at the same time, although a causal relationship has not been proven. Persistent vomiting during an infection may indicate the development of Reye's syndrome.
Prolonged use of drugs containing acetylsalicylic acid may cause headaches that worsen with each subsequent dose.
Prolonged 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 effect 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;
- the effect of anticoagulant, thrombolytic (dissolving blood clots), and antiplatelet (preventing platelet aggregation) drugs, 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 discontinuing systemic corticosteroid therapy (except for hydrocortisone used as replacement therapy in Addison's disease), the risk of salicylate overdose increases;
- the effect of digoxin (a heart medication), as it increases its serum concentration;
- the effect of antidiabetic drugs, such as insulin, sulfonylurea derivatives;
- the toxic effect of valproic acid (a medication used in epilepsy), which in turn enhances the anti-aggregatory effect of acetylsalicylic acid;
- the effect of selective serotonin reuptake inhibitors (antidepressants).
Special caution should be exercised when taking Alka-Seltzer with the following medicines, as acetylsalicylic acid weakens:
- the effect of uricosuric drugs (used to treat gout) that increase uric acid excretion from the body (e.g., benzbromarone, probenecid), which may worsen gout symptoms;
- the effect of diuretics;
- the effect of certain antihypertensive drugs (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.
Warning! Alcohol may increase the risk of adverse reactions from the gastrointestinal tract, such as stomach ulcers or bleeding.
Pregnancy, breastfeeding, and fertility
In pregnancy, during 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 labor.
Alka-Seltzer should not be taken during the first 6 months of pregnancy, unless it is absolutely necessary and has been prescribed by a doctor. If the patient requires treatment during this period or is trying to become pregnant, they should take 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 arterial duct 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 operating machinery
The medicine does not affect the ability to drive vehicles or operate machinery.
Alka-Seltzer contains sodium
One Alka-Seltzer tablet contains 477 mg of sodium (the main component of table 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.
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 doubt, 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 a minimum of 4 to 6 hours. Do not take more than 4000 mg of acetylsalicylic acid (i.e., a maximum of 12 effervescent tablets) per day.
Adolescents over 12 years of age:
The medicine may be taken by adolescents over 12 years of age only on the advice of a doctor.
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 not more often than every 4-6 hours.
Do not take more than 3 effervescent tablets (i.e., 972 mg of acetylsalicylic acid) 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. Take after meals.
Taking a higher dose of Alka-Seltzer than recommended
Poisoning with the active substance of Alka-Seltzer 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 are: dizziness (including vertigo), tinnitus, deafness, excessive sweating, nausea, and vomiting, headache, confusion (disorders of consciousness with disorientation, thought disorders, and speech disorders, delusions, hallucinations, anxiety, and psychomotor agitation), rapid breathing, too 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 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 their 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
If a dose is missed and symptoms persist, the next dose of Alka-Seltzer should be taken. 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 bloody vomit or black, tarry stools occur, the medicine should be discontinued and a doctor consulted.
- A symptom of a severe hypersensitivity reaction may be: facial and eyelid edema, tongue and laryngeal edema 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, immediate medical attention should be sought. These reactions can occur even after the first administration of the medicine.
The frequency of possible side effects listed below is as follows: frequent (in more than 1 patient in 100 but less than 1 in 10), rare (in more than 1 patient in 10,000 but less than 1 in 1,000), very rare (in less than 1 patient 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 (bloody vomit, black stools) or occult (more frequent with higher doses); stomach or duodenal ulcer, 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 concomitant use of other anticoagulant drugs) 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, manifested by 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, from the nose, from the gums, from the genitourinary system), hematomas.
Renal and urinary disorders:
Unknown:
Kidney 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 the administration of acetylsalicylic acid.
Reporting side effects
If any side effects occur, including any side effects not listed in the leaflet, the patient should inform their doctor, pharmacist, or nurse. Side effects can be reported directly to the Department of Monitoring of Adverse Reactions to Medicinal Products of the Office for Registration of Medicinal Products, Medical Devices, and Biocidal Products:
Aleje Jerozolimskie 181C
02-222 Warsaw
Phone: 22 49-21-301
Fax: 22 49-21-309
Website: https://smz.ezdrowie.gov.pl
Reporting side effects helps to gather more information on the safety of the medicine.
5. How to store Alka-Seltzer
Store in 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 packaging. 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. Package contents 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 dimethicone and calcium silicate, a mixture of sodium lauryl sulfate and sodium benzoate, sodium saccharin, lemon flavor, and lemon aroma.
What Alka-Seltzer looks like and what the package contains
One double sachet contains 2 effervescent tablets.
A cardboard box contains 10 effervescent tablets in the form of 5 double sachets, each containing 2 effervescent tablets.
For more detailed information, the patient should contact the marketing authorization holder or parallel importer.
Marketing authorization holder in Bulgaria, the country of export:
Bayer Bulgaria EOOD
Bul. Tsarigradsko Shose № 115 M, ground floor
1784 Sofia
Bulgaria
Manufacturer:
Bayer Bitterfeld GmbH
Salegaster Chaussee
06803 Bitterfeld-Wolfen
Germany
Parallel importer:
Delfarma Sp. z o.o.
ul. Św. Teresy od Dzieciątka Jezus 111
91-222 Łódź
Repackaged by:
Delfarma Sp. z o.o.
ul. Św. Teresy od Dzieciątka Jezus 111
91-222 Łódź
Authorization number in Bulgaria, the country of export: 20010171
Parallel import authorization number: 298/20
Date of leaflet approval: 11.04.2025
[Information about the trademark]

- Country of registration
- Dosage formTablets, 324 mg
- ATC codeN02BA01
- Active substance
- Prescription requiredNo
- Marketing authorisation holder (MAH)Bayer Bulgaria EOOD
- 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 acidManufacturer: Bayer Bitterfeld GmbH Pharma Innovations Sp. z o.o.Prescription not requiredDosage form: Tablets, 324 mgActive substance: acetylsalicylic acidPrescription not requiredDosage form: Tablets, 324 mgActive substance: acetylsalicylic acidPrescription not required
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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 Bulgaria EOOD. 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.
















