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Alka Seltzer Original Pain Relief - 10 Tablets

Alka Seltzer Original Pain Relief - 10 Tablets

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  • ✔️ Dissolves fast for quicker aspirin absorption than solid tablets
  • ✔️ Relieves headaches, fever, and cold and flu aches
  • ✔️ Contains sodium bicarbonate to help protect the stomach lining
  • ✔️ Suitable for adults and young people aged 16 and over
  • ✔️ Convenient 10-tablet pack for home or on-the-go use

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What Are Alka Seltzer Original Tablets and How Do They Help?

 

If you've ever had a pounding headache and needed something that works quickly, you'll know how frustrating it can be to wait for a tablet to kick in. Alka Seltzer Original tablets take a different approach. Rather than swallowing a solid tablet, you dissolve two effervescent tablets in a glass of water and drink the solution — meaning the aspirin gets to work faster than a standard tablet form. Each pack contains 10 tablets, making it a handy option to keep at home or in your bag. You can find this and other options across our pain relief collection at Cured Pharmacy.

Each tablet contains aspirin 324mg, sodium bicarbonate 1625mg, and citric acid 965mg. Together, these ingredients form a well-established formula that has been used for decades to relieve mild to moderate pain, including headaches, and to ease the aches and fever associated with colds and flu.

 

How Do Alka Seltzer Original Tablets Work?

 

Aspirin belongs to a class of medicines called non-steroidal anti-inflammatory drugs (NSAIDs). It works by blocking enzymes called COX-1 and COX-2, which are responsible for producing prostaglandins — the chemicals that trigger pain, inflammation, and fever in the body. Fewer prostaglandins means less pain signalling reaching your brain.

  • Aspirin inhibits prostaglandin synthesis, reducing pain and fever
  • Sodium bicarbonate acts as an antacid, helping to buffer stomach acid and reduce gastric irritation
  • Citric acid reacts with sodium bicarbonate to create the effervescent action, speeding up dissolution
  • The dissolved solution is absorbed more rapidly than a standard solid tablet

The effervescent delivery method is genuinely useful here. Because the aspirin is already in solution when you drink it, absorption from the gastrointestinal tract can begin more quickly compared with a conventional tablet that first needs to disintegrate and dissolve in the stomach.

 

Who Is Alka Seltzer Original Suitable For?

 

This product is designed for adults and young people aged 16 and over who need short-term relief from mild to moderate pain. It's particularly well suited to people who find solid tablets difficult to swallow, or who want a faster-acting format. That said, it's not right for everyone — read the contraindications carefully before use.

  • Adults aged 16 and over with headache or mild to moderate pain
  • People experiencing aches, fever, or discomfort associated with colds and flu
  • Those who prefer an effervescent, easy-to-drink format over solid tablets
  • People without a history of peptic ulcers, aspirin allergy, or NSAID sensitivity

 

How Do Alka Seltzer Original Tablets Compare to Standard Aspirin?

 

Feature Alka Seltzer Original Standard Aspirin Tablet
Form Effervescent tablet dissolved in water Solid tablet swallowed whole
Aspirin dose per tablet 324mg Typically 300mg or 75mg (low-dose)
Stomach protection Contains sodium bicarbonate (antacid) None (unless enteric-coated)
Speed of absorption Faster (pre-dissolved solution) Slower (must disintegrate first)

 

How Should You Store Alka Seltzer Original Tablets?

 

Store your Alka Seltzer Original tablets below 25°C in a dry place, away from direct sunlight and moisture. Effervescent tablets are particularly sensitive to humidity — even brief exposure to damp air can cause them to begin reacting prematurely, which reduces their effectiveness. Always keep the pack sealed until you're ready to use a tablet.

Keep all medicines out of the sight and reach of children. Do not use after the expiry date printed on the packaging. If you're managing multiple medicines at home, our first aid collection includes useful storage and health management products. Alka Seltzer Original tablets are for short-term use only — if your symptoms persist beyond three days, speak to your pharmacist or GP.

This product is a medicine. Speak to your doctor or pharmacist before using if you have an underlying medical condition or are taking other medicines.

Alka Seltzer Original Pain Relief - 10 Tablets specifications
Treatment category Pain relief / Antipyretic
Mechanism of action COX-1 and COX-2 inhibition (NSAID); antacid buffering via sodium bicarbonate
Effective for Headache, mild to moderate pain, fever, cold and flu symptoms
Suitable for Adults and young people aged 16 and over
Active ingredient Aspirin 324mg, Sodium bicarbonate 1625mg, Citric acid 965mg
Pack size 10 tablets
UK classification General Sale List (GSL)
Drug class NSAID / Analgesic / Antipyretic
Preparation Effervescent tablet
Route of administration Oral (dissolved in water)

Specifications of Alka Seltzer Original Pain Relief - 10 Tablets

 

What Is Alka Seltzer Original and What Is It Used For?

 

Alka Seltzer Original is an effervescent analgesic and antipyretic medicine. It contains aspirin as its active ingredient, supported by sodium bicarbonate and citric acid. It is used to relieve mild to moderate pain — most commonly headaches — and to reduce fever and ease the general aches associated with colds and flu. The effervescent format means you dissolve the tablets in water before drinking, which many people find easier and more comfortable than swallowing solid tablets.

It is available over the counter without a prescription and is classified as a General Sale List (GSL) medicine in the UK. It is intended for short-term use only and is not a substitute for medical treatment if your symptoms are severe or persistent.

 

What Do You Need to Know Before Using Alka Seltzer Original?

 

Before taking this medicine, it's important to check whether it is appropriate for you. Do not take Alka Seltzer Original if any of the following apply:

  • You are allergic to aspirin, any other NSAID (such as ibuprofen), or any ingredient in the tablet
  • You have or have had a peptic ulcer or gastrointestinal bleeding
  • You are under 16 years of age (risk of Reye's syndrome)
  • You have severe kidney, liver, or heart failure
  • You are in the last trimester of pregnancy
  • You are on a low-sodium diet (each tablet contains a significant amount of sodium)
  • You have haemophilia or another bleeding disorder

Speak to your pharmacist or GP before taking this medicine if you have asthma, gout, or mild to moderate kidney or liver problems. Also seek advice if you are pregnant or breastfeeding.

The following medicines may interact with Alka Seltzer Original:

  • Anticoagulants such as warfarin — increased risk of bleeding
  • Other NSAIDs or high-dose aspirin — increased risk of side effects
  • Methotrexate — aspirin can increase methotrexate toxicity
  • SSRIs (e.g. fluoxetine, sertraline) — increased risk of gastrointestinal bleeding
  • Antidiabetic medicines — aspirin may enhance their glucose-lowering effect
  • Corticosteroids — increased risk of gastrointestinal ulceration

 

How Should You Use Alka Seltzer Original?

 

Always use this medicine exactly as described on the label or as directed by your pharmacist. Do not exceed the stated dose.

  1. Fill a glass with at least 200ml (roughly a full tumbler) of water
  2. Drop 2 Alka Seltzer Original tablets into the water
  3. Wait until the tablets have fully dissolved — this usually takes around 1–2 minutes
  4. Stir gently if needed, then drink the solution immediately
  5. Do not swallow the tablets whole or chew them
Indication Age Group Dose Frequency
Headache / mild to moderate pain Adults and young people 16+ 2 tablets dissolved in water Every 4 hours, max 4 times daily (max 8 tablets in 24 hours)
Cold and flu symptoms / fever Adults and young people 16+ 2 tablets dissolved in water Every 4 hours, max 4 times daily (max 8 tablets in 24 hours)
Children under 16 Under 16 Do not use — risk of Reye's syndrome

If you are also managing cold and flu symptoms alongside pain, you may find it helpful to browse our cold and flu collection for additional supportive treatments.

 

What Are the Possible Side Effects of Alka Seltzer Original?

 

Like all medicines, Alka Seltzer Original can cause side effects, although not everyone experiences them. Knowing what to look out for helps you use this medicine safely.

Common side effects (may affect up to 1 in 10 people):

  • Nausea or stomach discomfort
  • Indigestion or heartburn
  • Mild stomach pain

Less common side effects (may affect up to 1 in 100 people):

  • Gastrointestinal bleeding (dark or tarry stools, vomiting blood — seek urgent medical attention)
  • Hypersensitivity reactions including skin rash, urticaria, or bronchospasm
  • Tinnitus (ringing in the ears) — particularly at higher doses
  • Fluid retention or raised blood pressure in susceptible individuals

Stop taking this medicine and seek immediate medical help if you develop signs of a serious allergic reaction, including swelling of the face, lips, or throat, difficulty breathing, or a severe skin reaction.

 

How Should You Store Alka Seltzer Original?

 

Correct storage keeps your tablets effective and safe to use. If you're building a home medicine cabinet, our vitamins and supplements collection also includes products that benefit from careful storage.

  • Store below 25°C in a dry place — avoid bathrooms or kitchens where humidity is high
  • Keep away from direct sunlight and heat sources
  • Keep the foil or tube sealed until you are ready to use a tablet
  • Keep out of the sight and reach of children
  • Do not use after the expiry date printed on the packaging
  • Do not dispose of medicines via wastewater or household waste — return unused tablets to your pharmacy

Written and reviewed by our qualified team

Your safety and success are our highest priorities. Our medical team rigorously evaluates every product and piece of advice we provide, ensuring you receive only the most effective, science-backed solutions available.

Frequently Asked Questions

Where can I buy Alka Seltzer Original tablets online in the UK?

You can buy Alka Seltzer Original tablets directly from Cured Pharmacy, a GPhC-registered UK online pharmacy. The 10-tablet pack is available for just £3.25 with fast UK delivery. Browse our full pain relief collection for more options.

How do Alka Seltzer Original tablets work in the body?

Alka Seltzer Original tablets contain aspirin, which works by inhibiting COX-1 and COX-2 enzymes, reducing the production of prostaglandins — the chemicals responsible for pain, inflammation, and fever. Sodium bicarbonate buffers stomach acid to help protect the gastric lining and may speed up absorption. The effervescent format means the aspirin is already dissolved when you drink it, allowing it to be absorbed more quickly than a standard solid tablet.

How do I use Alka Seltzer Original tablets step by step?

Drop 2 tablets into a glass containing at least 200ml of water and wait for them to fully dissolve before drinking. Never swallow the tablets whole or chew them — they must be fully dissolved first. Drink the solution as soon as it is ready for best results.

What is the correct dose of Alka Seltzer Original for adults?

The recommended adult dose is 2 tablets dissolved in water, taken up to 4 times per day. Leave at least 4 hours between doses and do not exceed 8 tablets (4 doses) in any 24-hour period. Always follow the instructions on the pack or as directed by your pharmacist.

When is the best time to take Alka Seltzer Original tablets?

Take Alka Seltzer Original as soon as your symptoms begin — early use tends to give the best results for headache relief. Taking it with or after food may help reduce the chance of stomach discomfort, even though the sodium bicarbonate already provides some gastric protection. Space doses evenly throughout the day if you need repeat doses.

What are the side effects of Alka Seltzer Original tablets?

The most common side effects are nausea, stomach discomfort, and indigestion. Less commonly, some people may experience gastrointestinal bleeding, tinnitus, or hypersensitivity reactions such as skin rash or breathing difficulties. Stop taking the tablets and seek medical advice immediately if you notice any serious or unexpected symptoms.

How do I manage side effects of Alka Seltzer Original?

If you experience mild stomach discomfort, try taking the dissolved solution with or after a light meal or snack. Avoid lying down immediately after taking the medicine. If side effects are persistent or severe — particularly any signs of gastrointestinal bleeding such as dark stools or vomiting blood — stop use and contact your GP or call 111 immediately.

Who should not take Alka Seltzer Original tablets?

Alka Seltzer Original is not suitable for children under 16 due to the risk of Reye's syndrome, a rare but serious condition. It should also be avoided by people with aspirin or NSAID allergy, active peptic ulcers, severe kidney or liver disease, bleeding disorders, or those in the last trimester of pregnancy. People on a low-sodium diet should be aware that each tablet contains a significant amount of sodium.

Can I take Alka Seltzer Original with other medicines?

Alka Seltzer Original can interact with several medicines, including anticoagulants like warfarin (increased bleeding risk), other NSAIDs, methotrexate, SSRIs, corticosteroids, and antidiabetic medicines. Always tell your pharmacist about all medicines you are currently taking before starting Alka Seltzer Original. If you are unsure, speak to a pharmacist before use.

Is Alka Seltzer Original safe to take during pregnancy?

Alka Seltzer Original should not be taken during the third trimester of pregnancy as aspirin may harm the unborn baby and affect labour. During the first and second trimesters, use should only be considered on medical advice. If you are pregnant or planning a pregnancy, always speak to your GP or midwife before taking any pain relief medicine.

Can I take Alka Seltzer Original if I have asthma?

Some people with asthma are sensitive to aspirin and other NSAIDs, and taking them can trigger bronchospasm or worsen breathing. If you have asthma, speak to your GP or pharmacist before taking Alka Seltzer Original. There are alternative pain relief options that may be more suitable for you.

What happens if I miss a dose of Alka Seltzer Original?

Because Alka Seltzer Original is taken as needed for pain relief rather than on a fixed schedule, a missed dose simply means you take the next dose when your symptoms return or worsen. Do not double up doses to compensate — always leave at least 4 hours between doses. If your pain is persistent, speak to your pharmacist.

How long can you take Alka Seltzer Original for?

Alka Seltzer Original is intended for short-term use only — no more than 3 consecutive days without medical advice. If your symptoms persist beyond this time, worsen, or are accompanied by other concerning symptoms, you should consult your GP. Prolonged use of aspirin without medical supervision can increase the risk of gastrointestinal side effects.

What are the alternatives to Alka Seltzer Original tablets?

Common alternatives for mild to moderate pain relief include paracetamol and ibuprofen, both of which are available over the counter. Paracetamol is often preferred for people who cannot tolerate aspirin or NSAIDs. You can explore a range of options in our pain relief collection to find the most suitable product for your needs.

What are the latest studies on aspirin for headache relief?

Aspirin remains a well-established and clinically supported treatment for mild to moderate pain, including tension headaches, as recognised by the NHS and the British National Formulary. Research continues to support its analgesic and antipyretic properties when used at appropriate doses. For the most up-to-date clinical guidance, refer to NHS.uk or speak to your pharmacist or GP.

How Should You Use Alka Seltzer Original?

Using Alka Seltzer Original correctly is straightforward, but it's worth following the steps carefully to get the most from each dose. The tablets must always be dissolved in water before you drink them — never swallow them whole or allow them to dissolve in your mouth.

What Is the Correct Dose of Alka Seltzer Original?

The dose varies depending on the age of the person taking it. This medicine is not suitable for children under 16 years of age. Always follow the dosage instructions on the pack and never exceed the maximum daily dose.

When Is the Best Time to Use Alka Seltzer Original?

Take Alka Seltzer Original as soon as your symptoms begin — acting early tends to give the most effective relief, particularly for headaches. If you find the medicine causes mild stomach discomfort, taking it with or shortly after a light meal or snack may help, even though the sodium bicarbonate in the formula already provides some gastric buffering.

Space your doses evenly throughout the day if you need more than one dose, and always leave at least 4 hours between each dose. Avoid taking a dose late at night unless necessary, as aspirin can occasionally cause mild sleep disturbance in sensitive individuals.

How Long Can You Use Alka Seltzer Original For?

Alka Seltzer Original is designed for short-term use only. Do not use it for more than 3 consecutive days without speaking to your pharmacist or GP. If your pain or fever has not improved within this time, or if your symptoms worsen at any point, seek medical advice promptly.

Long-term or frequent use of aspirin-containing medicines without medical supervision can increase the risk of gastrointestinal side effects, including stomach ulcers and bleeding. If you find yourself needing pain relief regularly, it is worth discussing this with your GP to identify any underlying cause.

Do not exceed the recommended dose. If in doubt, speak to your pharmacist.

What Are the Most Common Side Effects of Alka Seltzer Original?

Most people tolerate Alka Seltzer Original well when taken at the recommended dose for a short period. However, as with all aspirin-containing medicines, some people do experience side effects — particularly affecting the stomach and digestive system.

  • Nausea or feeling sick
  • Stomach discomfort or mild pain
  • Indigestion or heartburn
  • Bloating

Taking the dissolved solution with or after food may help reduce the likelihood of these effects. The sodium bicarbonate in the formula provides some gastric buffering, but it does not eliminate the risk entirely.

What Are the Less Common Side Effects of Alka Seltzer Original?

Less commonly, some people may experience more noticeable side effects. These are worth being aware of, even if they are unlikely to affect you.

  • Tinnitus (ringing or buzzing in the ears) — more likely at higher doses
  • Dizziness or light-headedness
  • Skin rash or itching
  • Fluid retention or mild swelling
  • Increased blood pressure in susceptible individuals

If you notice tinnitus while taking this medicine, stop use and speak to your pharmacist or GP, as this can be a sign that the aspirin dose is too high for you.

What Are the Serious Side Effects of Alka Seltzer Original?

Serious side effects are uncommon but require immediate medical attention if they occur. Gastrointestinal bleeding is the most significant risk associated with aspirin use. Signs include dark or tarry stools, vomiting blood or material that looks like coffee grounds, or severe abdominal pain. Stop taking the medicine immediately and call 999 or go to your nearest A&E if you experience any of these symptoms.

Serious allergic reactions (anaphylaxis) are rare but possible. Symptoms include swelling of the face, lips, tongue, or throat, difficulty breathing, a rapid heartbeat, or a sudden drop in blood pressure. This is a medical emergency — call 999 immediately.

What Should You Do If You Experience Side Effects?

For mild side effects such as nausea or indigestion, try taking the dissolved solution with food and ensure you are drinking enough water. If side effects are persistent, uncomfortable, or worsen over time, stop taking the medicine and speak to your pharmacist. They can advise whether an alternative pain relief option might be more suitable for you.

You can report suspected side effects directly to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk. Reporting side effects helps improve medicine safety for everyone.

Can Alka Seltzer Original Interact With Other Medicines?

Yes — aspirin has several clinically significant drug interactions that you should be aware of before taking Alka Seltzer Original. Always inform your pharmacist of all medicines you are currently taking, including over-the-counter products and herbal remedies.

  • Anticoagulants (e.g. warfarin, heparin) — significantly increased risk of bleeding
  • Other NSAIDs (e.g. ibuprofen, naproxen) — increased risk of gastrointestinal side effects
  • Methotrexate — aspirin can reduce its excretion, increasing toxicity risk
  • SSRIs (e.g. fluoxetine, sertraline) — increased risk of gastrointestinal bleeding
  • Corticosteroids — increased risk of peptic ulceration
  • Antidiabetic medicines — aspirin may enhance blood glucose-lowering effects
  • ACE inhibitors and diuretics — aspirin may reduce their effectiveness

If you are concerned about any side effects, contact your pharmacist or GP immediately.

Patient Information Leaflet

Important - Before taking any medication, it is always important to read the Patient Information Leaflet (PIL)

Written and reviewed by our qualified team

GPhC Number: 2233073
Tarun Kumar

Reviewed by:

Tarun Kumar

Superintendent/ Clinical Lead

📖 Find out more about our team of medical content authors and how we ensure the accuracy of our content with our content guidelines.

Content last updated: 31 Mar 2025

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