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ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS

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About the medicine

How to use ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS

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This page provides general information and does not replace a doctor’s consultation. Always consult a doctor before taking any medication. Seek urgent medical care if symptoms are severe.

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Introduction

Package Leaflet: Information for the User

ALKA-SELTZER2.1 gEffervescent Tablets

Sodium Hydrogen Carbonate

Read the package leaflet carefully before starting to use this medicine because it contains important information for you.

Follow the administration instructions of the medicine contained in this package leaflet or as indicated by your doctor or pharmacist.

  • Keep this package leaflet, as you may need to read it again.
  • If you need advice or more information, consult your pharmacist.
  • If you experience side effects, consult your doctor or pharmacist, even if it is a side effect not listed in this package leaflet. See section 4.
  • You should consult a doctor if it worsens or does not improve after 14 days.

Contents of the Package Leaflet:

  1. What is Alka-Seltzer and what is it used for
  2. What you need to know before taking Alka-Seltzer
  3. How to take Alka-Seltzer
  4. Possible side effects
  5. Storage of Alka-Seltzer
  6. Package Contents and Additional Information

1. What is Alka-Seltzer and what is it used for

It belongs to the group of medicines called antacids that work by reducing excess stomach acidity.

This medicine is indicated for the symptomatic relief of heartburn and stomach acid in adults and adolescents from 12 years old.

Doctor consultation

Not sure if this medicine is right for you?

Discuss your symptoms and treatment with a doctor online.

2. What you need to know before taking Alka-Seltzer

Do not take ALKA-SELTZER:

  • If you are allergic to sodium hydrogen carbonate or any of the other components of this medicine (listed in section 6).
  • If you have metabolic or respiratory alkalosis.
  • If you have hypocalcemia
  • If you have hypochlorhydria
  • If you have a tendency to form edema (fluid retention).
  • If you have appendicitis or its symptoms (nausea, vomiting, cramps, abdominal pain).
  • If you have intestinal obstruction (partial or total blockage of the intestine that produces an interruption of the passage of intestinal contents through it).

Warnings and Precautions

Consult your doctor or pharmacist before taking Alka-Seltzer.

As with other antacids, this medicine may mask the symptoms of a more serious stomach disease, so if the symptoms persist or worsen after 14 days of treatment, you should consult your doctor.

It is recommended to use this medicine with caution in patients with hypertension (high blood pressure), in patients with liver, kidney, and heart disease, edema, hypokalemia, hypocalcemia, and aldosteronism (syndrome associated with increased secretion of aldosterone by the adrenal gland) and in patients undergoing diuretic treatment as it may produce hypochloremic alkalosis.

Taking Alka-Seltzer at high doses or for prolonged periods could lead to metabolic alkalosis.

Due to its citric acid content, it is recommended to use with caution in patients with uric acid stones as it may favor the formation of calcium stones.

Children and Adolescents

Do not administer this medicine to children under 12 years old.

Taking Alka-Seltzer with other medicines

Tell your doctor or pharmacist if you are taking, have recently taken, or may take any other medicine.

This is especially important in the case of:

  • ketoconazole (used to treat fungal infections)
  • quinolones, tetracyclines (especially doxycycline), acidic forms of sulfonamide, erythromycin, methenamine (different classes of antibiotics)
  • iron salts (medicines used to prevent or treat anemia)
  • naproxen, salicylates (used to treat pain and fever),
  • valproic acid (used to treat epilepsy)
  • levodopa (used to treat Parkinson's disease)
  • amphetamines, dexamphetamine, ephedrine (central nervous system stimulants)
  • cardiac antiarrhythmics
  • methadone (used to relieve intense pain)
  • meCamylamine (medicine for hypertension)
  • lithium salts (used in some psychiatric illness)
  • barbiturates
  • methotrexate (used to treat cancer and rheumatoid arthritis)
  • preparations containing calcium, as it may develop the milk-alkali syndrome whose symptoms are: excess calcium in the blood, kidney problems, heart problems, metabolic alkalosis, dizziness, vomiting, muscle cramps, apathy, headache, confusion states, and anorexia.

As with other antacids, this medicine administered with enteric-coated medicines may cause the coating to dissolve too quickly, which can produce gastric or duodenal irritation.

Antacids modify the absorption of numerous medicines, so in general, their administration should be spaced out from any other medicine. In general, the intake of this medicine should be done at least 2 hours before or after the administration of any other medicine.

Tell your doctor or pharmacist if you are taking or have recently taken any other medicine, even those purchased without a prescription.

Interference with diagnostic tests:

If you are going to have any diagnostic test (including blood tests, urine tests, detection of gastric acid secretion, etc.), inform your doctor that you are taking this medicine, as it may alter the results.

Taking ALKA-SELTZER with food and drinks:

Do not take this medicine with milk or dairy products.

Due to its sodium hydrogen carbonate content, this medicine should not be taken immediately after excessive food or drink, as it may cause an increase in carbon dioxide production, which could lead to gastric distension and, in rare cases, may perforate the stomach walls.

Pregnancy, Breastfeeding, and Fertility

If you are pregnant or breastfeeding, or think you may be pregnant or plan to become pregnant, consult your doctor or pharmacist before using this medicine.

Driving and Using Machines:

No effect of Alka-Seltzer on the ability to drive and use machines has been described.

Alka-Seltzer contains Sodium and Aspartame (E-951).

This medicine contains 570 mg of sodium (main component of table salt/cooking salt) in each effervescent tablet. This is equivalent to 28.5% of the maximum recommended sodium intake for an adult.

Consult your doctor or pharmacist if you need 6 or more effervescent tablets per day for a prolonged period, especially if you have been recommended a low-salt diet (sodium).

This medicine contains 10 mg of aspartame in each effervescent tablet. Aspartame contains a source of phenylalanine that may be harmful in case of phenylketonuria (PKU), a rare genetic disease in which phenylalanine accumulates because the body is unable to eliminate it properly.

3. How to take Alka-Seltzer

Follow the administration instructions of this medicine contained in this package leaflet or as indicated by your doctor or pharmacist. In case of doubt, ask your doctor or pharmacist.

This medicine is administered orally.

The recommended dose is:

Adults and adolescents from 12 years old: The usual dose is 1 effervescent tablet, if necessary increased to 2, after meals or when feeling gastric discomfort.

Do not exceed 6 tablets per day.

Elderly over 65 years: Do not exceed 3 tablets per day.

Patients with renal insufficiency

They should consult their doctor before taking this medicine.

Use in children and adolescents

Do not use in children under 12 years old.

Always use the lowest effective dose.

If you think the effect of ALKA-SELTZER is too strong or too weak, tell your doctor or pharmacist.

Do not take this medicine with a stomach excessively full of food or drink. You should wait between 20 minutes and 1 hour after meals before taking the medicine. It is necessary to wait until the effervescent tablet has completely dissolved in water and the bubbling has disappeared before taking it. Consult your doctor if you notice a strong stomach pain after taking the medicine.

The administration of this preparation is subject to the appearance of gastric discomfort. As they disappear, this medication should be suspended.

If the symptoms persist for more than 14 days or worsen or other symptoms appear, you should interrupt the treatment and consult your doctor.

If you take more ALKA-SELTZER than you should

The main symptoms of overdose are metabolic alkalosis (headache, dizziness, ringing in the ears, blurred vision, drowsiness, sweating, nausea, vomiting, occasionally diarrhea, hyperirritability, and tetany (muscle weakness)) and fluid retention.

In case of overdose or accidental ingestion, consult your doctor or pharmacist immediately or go to a medical center immediately or call the Toxicology Information Service, phone: 91 562 04 20, indicating the medicine and the amount ingested.

If you forget to take ALKA-SELTZER:

Do not take a double dose to make up for forgotten doses.

Medicine questions

Started taking the medicine and have questions?

Discuss your symptoms and treatment with a doctor online.

4. Possible side effects

Like all medicines, Alka-Seltzer can cause side effects, although not everyone gets them.

Adverse reactions are listed in decreasing order of severity within each frequency interval.

The convention used for the definition of frequencies is as follows: very common (≥1/10); common (≥1/100 to <1>

Frequency not known (frequency cannot be estimated from available data):Flatulence (gas in the stomach or intestine), belching, vomiting, cramps, stomach distension, and rebound effect (increase in acidity produced by the medicine itself).

Hypokalemia (decrease in potassium levels in the blood) and hypernatremia (increase in sodium levels in the blood).

If used continuously or at high doses, it may produce systemic alkalosis, whose symptoms include difficulty breathing, muscle weakness, increased muscle tone, spasms, tetany (involuntary muscle contraction), especially with hypercalcemia, anxiety, and other effects on the central nervous system.

Hypertension (high blood pressure) and edema (fluid retention) if used continuously or at high doses.

With unknown frequency, oral ingestion of Sodium Hydrogen Carbonate has caused spontaneous gastric perforation due to gas production.

Excessive oral administration of medicines containing citrate salts may have a laxative effect.

Reporting of side effects:

If you experience any side effect, consult your doctor or pharmacist, even if it is a possible side effect not listed in this package leaflet. You can also report them directly through the Spanish Medicines and Health Products Agency's website: http://www.notificaram.es. By reporting side effects, you can help provide more information on the safety of this medicine.

5. Storage of Alka-Seltzer

Keep this medicine out of the sight and reach of children.

Keep the container tightly closed.

Do not use Alka-Seltzer after the expiration date stated on the container, after the abbreviation CAD. The expiration date is the last day of the month indicated.

Medicines should not be disposed of via wastewater or household waste. Place the containers and medicines you no longer need in the pharmacy's SIGRE collection point. If in doubt, ask your pharmacist how to dispose of containers and medicines you no longer need. This will help protect the environment.

6. Package Contents and Additional Information

Composition of Alka-Seltzer

  • The active ingredient is Sodium Hydrogen Carbonate. Each effervescent tablet contains 2.1 g (2081.8 mg) of sodium hydrogen carbonate (sodium bicarbonate).
  • The other ingredients (excipients) are citric acid, aspartame (E-951), mannitol (E-421), acesulfame potassium, lemon-lime flavor, vanilla flavor, and amiflex (a compound of amino acids, glutamic acid, and sodium chloride).

Appearance of the product and package contents:

This medicine is effervescent tablets, round and white in color. They are available in containers of 10 or 20 effervescent tablets.

Some container sizes may not be marketed.

Marketing Authorization Holder

BAYER HISPANIA, S.L.

Av. Baix Llobregat, 3-5

08970 Sant Joan Despí (Barcelona)

Manufacturer:

BAYER BITTERFELD GmbH

OT Greppin

Salegaster Chaussee, 1

06803 Bitterfeld-Wolfen

Germany

Date of the last revision of this package leaflet: September 2019

Detailed and updated information on this medicine is available on the website of the Spanish Agency for Medicines and Health Products (AEMPS) http://www.aemps.es/

Online doctors for ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS

Discuss questions about ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS, including use, safety considerations and prescription review, subject to medical assessment and local regulations.

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Doctor

Hocine Lokchiri

General medicine 21 years exp.

Dr. Hocine Lokchiri is a French consultant with over 20 years of experience in General and Emergency Medicine. He works with adults and children, helping patients with urgent symptoms, infections, sudden health changes and everyday medical concerns that require timely evaluation. His background includes clinical practice in France, Switzerland and the United Arab Emirates, which allows him to navigate different healthcare systems and manage a wide range of conditions with confidence. Patients value his calm, structured approach, clear explanations and evidence-based decision-making.

Online consultations with Dr. Lokchiri are suitable for many situations when someone needs quick medical guidance, reassurance or a clear next step. Common reasons for booking include:

  • fever, chills, fatigue and viral symptoms
  • cough, sore throat, nasal congestion, breathing discomfort
  • bronchitis and mild asthma flare-ups
  • nausea, diarrhoea, abdominal pain, digestive infections
  • rashes, allergic reactions, redness, insect bites
  • muscle or joint pain, mild injuries, sprains
  • headache, dizziness, migraine symptoms
  • stress-related symptoms, sleep disturbances
  • questions about test results and treatment plans
  • management of chronic conditions in stable phases
Many patients reach out when symptoms appear suddenly and cause concern, when a child becomes unwell unexpectedly, when a rash changes or spreads, or when it’s unclear whether an in-person examination is necessary. His emergency medicine background is particularly valuable online, helping patients understand risk levels, identify warning signs and choose safe next steps.

Some situations are not suitable for online care. If a patient has loss of consciousness, severe chest pain, uncontrolled bleeding, seizures, major trauma or symptoms suggesting a stroke or heart attack, he will advise seeking immediate local emergency services. This improves safety and ensures patients receive the right level of care.

Dr. Lokchiri’s professional training includes:

  • Advanced Trauma Life Support (ATLS)
  • Basic and Advanced Cardiac Life Support (BLS/ACLS)
  • Pediatric Advanced Life Support (PALS)
  • Prehospital Trauma Life Support (PHTLS)
  • eFAST and critical care transthoracic echocardiography
  • aviation medicine
He is an active member of several professional organisations, including the French Society of Emergency Medicine (SFMU), the French Association for Emergency Physicians (AMUF) and the Swiss Society of Emergency and Rescue Medicine (SGNOR). In consultations, he works with clarity and precision, helping patients understand their symptoms, possible risks and the safest treatment options.
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€58
5.0 (25)
Doctor

Lina Travkina

Family medicine 13 years exp.

Dr. Lina Travkina is a licensed family and preventive medicine doctor based in Italy. She provides online consultations for adults and children, supporting patients across all stages of care – from acute symptom management to long-term health monitoring and prevention.

Areas of medical care include:

  • Respiratory conditions: colds, flu, acute and chronic bronchitis, mild to moderate pneumonia, bronchial asthma.
  • ENT and eye conditions: sinusitis, tonsillitis, pharyngitis, otitis, infectious and allergic conjunctivitis.
  • Digestive issues: gastritis, acid reflux (GERD), IBS, dyspepsia, bloating, constipation, diarrhoea, functional bowel symptoms, intestinal infections.
  • Urological and infectious diseases: acute and recurrent cystitis, bladder and kidney infections, prevention of recurrent UTIs, asymptomatic bacteriuria.
  • Chronic conditions: hypertension, diabetes, hypercholesterolemia, metabolic syndrome, thyroid disorders, excess weight.
  • Neurological and general symptoms: headache, migraine, dizziness, fatigue, sleep disturbances, reduced concentration, anxiety, asthenia.
  • Chronic pain support: back, neck, joint, and muscle pain, tension syndromes, pain associated with osteochondrosis and chronic conditions.

Additional care areas:

  • Preventive consultations and check-up planning.
  • Medical advice and follow-up consultations.
  • Test interpretation and diagnostic guidance.
  • Structured support for undiagnosed complaints.
  • Second opinion on diagnoses and treatment plans.
  • Nutritional and lifestyle support for vitamin deficiencies, anaemia, metabolic issues.
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Dr. Travkina combines evidence-based medicine with an attentive, personalised approach. Her consultations focus not only on treatment, but also on prevention, recovery, and long-term wellbeing.

If during the consultation it becomes clear that your case requires in-person assessment or specialised care outside of her scope, the session will be terminated and the payment fully refunded.

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€70
5.0 (760)
Doctor

Alina Tsurkan

Family medicine 13 years exp.

Dr. Alina Tsurkan is a licensed family medicine physician based in Portugal, offering online consultations for adults and children. She provides professional primary care, with a focus on prevention, accurate diagnosis, and long-term management of acute and chronic conditions.

Dr. Tsurkan supports patients with a wide range of health issues, including:

  • Respiratory infections: cold, flu, bronchitis, pneumonia, and lingering coughs.
  • ENT conditions: sinusitis, tonsillitis, otitis (ear infections), sore throat, allergic rhinitis.
  • Eye conditions: allergic or infectious conjunctivitis, red eyes, irritation.
  • Digestive issues: acid reflux (GERD), gastritis, irritable bowel syndrome (IBS), constipation, bloating, nausea.
  • Urinary and reproductive health: urinary tract infections (UTIs), cystitis, prevention of recurrent infections.
  • Chronic diseases: hypertension, elevated cholesterol, weight management.
  • Neurological complaints: headaches, migraines, sleep disturbances, fatigue, general weakness.
  • Children’s health: fever, infections, digestive issues, follow-ups, vaccination guidance.

She also provides:

  • IMT medical certificates for driving licence exchange in Portugal.
  • Personalised preventive care and wellness consultations.
  • Interpretation of test results and medical reports.
  • Follow-up care and medication review.
  • Support in managing multiple coexisting conditions.
  • Remote prescription management and medical documentation.

Dr. Tsurkan’s approach is evidence-based and holistic. She works closely with each patient to develop an individualised care plan that addresses both symptoms and root causes. Her goal is to empower patients to take control of their health and maintain well-being through lifestyle adjustments, routine check-ups, and early intervention.

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Frequently Asked Questions

Is a prescription required for ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS?
ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS does not require a prescription in Spain. You can check with a doctor online whether this medicine may be appropriate for your situation.
Who manufactures ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS?
ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS is manufactured by Bayer Hispania S.L.. Pharmacy brands and packaging may differ depending on the distributor.
Which doctors can assess the use of ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS online?
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 2.1 g EFFERVESCENT TABLETS is appropriate, depending on your situation and local regulations. You can book an online consultation to discuss your symptoms and possible next steps.
What are the alternatives to ALKA-SELTZER 2.1 g EFFERVESCENT TABLETS?
Other medicines with the same active substance () include BICARBONATE 1 g POWDER FOR ORAL SOLUTION, ACYLINE 620 mg/380 mg/630 mg ORAL SUSPENSION, ALMAGATO STADAPHARM 1.5 G ORAL SUSPENSION. 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.
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