Patient leaflet - Aspirin tablets BP 300 mg
1. What Aspirin 300mg Tablets are and what they are used for
- The name of your medicine is Aspirin 300mg Tablets. It contains the active ingredient Aspirin 300 mg.
- Aspirin belongs to a group of medicines called the non-steroidal anti- inflammatory drugs (NSAIDs). It relieves mild to moderate pain, reduces inflammation and lowers temperature when you have a fever.
It is recommended for:
- Relief of headache, toothache, migraine, neuralgia, sore throat, period pains, aches and pains.
- Relief of the symptoms of inflammatory conditions including sprains, strains, rheumatic pain, sciatica, lumbago, fibrositis, muscular aches and pains, joint swelling and stiffness.
- Relief of the symptoms of cold and influenza.
2. What you need to know before you take Aspirin 300mg Tablets
Do not take Aspirin Tablets if you:
- are allergic to Aspirin or any other painkillers (NSAIDs) or to any of the other ingredients contained in the tablets. You may have developed difficulty breathing, runny nose, rash, or swollen face or lips, after taking aspirin or a NSAID previously (see section 6)
- have a stomach ulcer or history of ulcers or indigestion have nasal polyps associated with asthma
Read all of this leaflet carefully before you start taking this medicine because it contains important information for you.
Always take this medicine exactly as described in this leaflet or as your doctor or pharmacist or nurse has told you.
- Keep this leaflet. You may need to read it again.
- Ask your pharmacist if you need more information or advice.
- If you get any side effects, talk to your doctor or pharmacist or nurse. This includes any possible side effects not listed in this leaflet. See Section 4.
- You must talk to a doctor if you do not feel better or if you feel worse.
- have haemophilia or other blood clotting disorder or are taking medicines to thin the blood
- have severe liver or severe kidney problems or severe heart failure
- are in the last 3 months of your pregnancy, you must not use higher doses than 100mg per day (see section “Pregnancy, breast-feeding and fertility”).
- are child under 16 years old
- are taking methotrexate (15mg a week)
- have gout
Important warning:
There is a possible association between aspirin and Reye’s Syndrome when given to children. Reye’s syndrome is a very rare disease, which can be fatal. For this reason aspirin should not be given to children aged under 16 years, unless on the advice of a doctor e.g. for Kawasaki’s Disease.
Taking a painkiller for headaches too often or for too long can make them worse.
Warnings and Precautions
Talk to your doctor or pharmacist or nurse before taking Aspirin Tablets if you:
- suffer from asthma, or other allergies.
- have heart, liver or kidney problems or gout
- have an overactive thyroid gland
- are dehydrated (you may feel thirsty and have a headache, dry mouth and lips)
- have anaemia or suffer from a deficiency of the enzyme glucose- 6- phosphate dehydrogenase (G6PD) this can cause episodes of anaemia after eating certain foods such as fava beans (favism)
- have systemic lupus erythematosus (SLE) or other connective tissue disease
- are elderly
- have had any disorders affecting blood vessels in the brain
- have received a varicella (chickenpox) vaccination within the last 6 weeks
- are pregnant or breast-feeding.
- have heavy bleeding during your periods
- have a history of stomach ulcers
- have chronic respiratory disease
- have hypertension
- taking deferasirox (a medicine to remove excess iron from the body)
When taking acetylsalicylic acid, serious allergic reactions which may include chest pain and even heart attack (Kounis syndrome) have been reported (see section 4). Seek medical care immediately when you notice chest pain with allergic reactions (such as skin rashes, shortness of breath).
Other medicines and Aspirin Tablets:
Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines including medicines obtained without a prescription. Especially:
- warfarin, coumarin, heparin, phenindione, dipyridamole and clopidogrel (used to prevent blood clotting)
- metoclopramide or domperidone (to prevent sickness)
- diuretics (“water tablets”) such as spironolactone, furosemide, acetazolamide (to treat high blood pressure)
- medicines which make your urine more alkaline such as antacids, citrates
- probenecid (to treat gout)
- methotrexate (to treat some cancers, psoriasis and rheumatic disease)
- sulphonylureas or insulin (antidiabetics)
- phenytoin or sodium valproate (to treat epilepsy)
- corticosteroids (to suppress the immune system)
- mifepristone (to induce abortion)
- other non-steroidal anti-inflammatory drugs - NSAIDs (such as ibuprofen or naproxen)
- metamizole (substance to decrease pain and fever) may reduce the effect of aspirin on platelet aggregation (blood cells sticking together and forming a blood clot), when taken at the same time. Therefore, this combination should be used with caution in patients taking low dose aspirin for cardio protection
- vancomycin (medicines which can cause hearing problems)
- medicines to treat high blood pressure such as ACE inhibitors (e.g. enalapril, lisinopril, perindopril), Calcium channel blockers (e.g. amlodipine, diltiazem, nifedipine)
- SSRIs such as sertraline or paroxetine (medicines to treat depression)
- varicella (chickenpox) vaccine. Aspirin should be avoid for 6 weeks after vaccination
- herbal medicines containing ginkgo biloba.
- digoxin (to treat heart problems)
- lithium (to treat depression)
- acetazolamide (to treat glaucoma)
- cyclosporine, tacrolimus (used to prevent organ rejection)
- alcohol
Aspirin Tablets with food, drink and alcohol
Avoid alcohol whist taking this medicine.
Pregnancy, breast-feeding and fertility
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine. Avoid taking Aspirin tablets during pregnancy especially in the last 3 months of pregnancy or whilst breast-feeding.
If you continue or start treatment with Aspirin Tablets during pregnancy per instruction of the physician, then use Aspirin Tablets as advised by your doctor and do not use a higher dose than is recommended.
Pregnancy - last trimester
Do not take Aspirin Tablets higher than 100 mg per day if you are in the last 3 months of pregnancy as it could harm your unborn child or cause problems at delivery. It can cause kidney and heart problems in your unborn baby. It may affect your and your baby’s tendency to bleed and cause labour to be later or longer than expected.
If you take Aspirin Tablets at low doses (up to and including 100 mg per day), you need strict obstetric monitoring as advised by your doctor.
Pregnancy – first and second trimester
You should not take Aspirin Tablets during the first 6 months of pregnancy unless absolutely necessary and advised by your doctor. If you need treatment during this period or while you are trying to get pregnant, the lowest dose for the shortest time possible should be used. If taken for more than a few days from 20 weeks of pregnancy onward, Aspirin Tablets can cause kidney problems in your unborn baby that may lead to low levels of amniotic fluid that surrounds the baby (oligohydramnios) or narrowing of a blood vessel (ductus arteriosus) in the heart of the baby. If you need treatment for longer than a few days, your doctor may recommend additional monitoring.
Surgery and tests
If you need to have an operation including having your teeth removed or blood and urine tests, tell your doctor or dentist you are taking this medicine.
Aspirin Tablets contains lactose
Aspirin Tablets contains lactose. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product.
3. How to take Aspirin 300mg Tablets
Always take this medicine exactly as described in this leaflet or as your doctor or pharmacist or nurse has told you. Check with your doctor or pharmacist or nurse if you are not sure.
Swallow the tablets with a glass of water.
Doses:
Adults, including the older people:
1 or 2 tablets every 3 to 4 hours as required. No more than 12 tablets in any 24-hour period.
For prevention of blood clots:
The recommended dose is 1 tablet once a day
Use in children and adolescents
Aspirin tablets are not recommended for use in children and adolescents
younger than 16 years
If you take more Aspirin tablets than you should
If you (or someone else) swallow a lot of tablets at the same time, or you think a child may have swallowed any contact your nearest hospital casualty department or tell your doctor immediately. Symptoms of an overdose include ringing in the ears, spinning sensation, fast breathing rate, changes in some of the chemicals in the body, heart failure, changes in body temperature resulting dehydration, restlessness, fits, hallucination (seeing or hearing things that are not there), headache, hearing problems, confusion, feeling or being sick, stomach pain or coma.
If you forget to take Aspirin tablets
Do not take a double dose to make up for a forgotten dose. If you forget to take a dose take it as soon as you remember it and then take the next dose at the right time. Do not take more than one dose in any 4 hour period.
If you have any further questions on the use of this medicine, ask your doctor or pharmacist or nurse.
4. Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them.
Stop taking this medicine and contact a doctor immediately if you have any of the following:
- Difficulty breathing
- Severe allergic reactions (blistered skin, swelling of the face, lips, throat or tongue, difficulty breathing, worsening of asthma, shock)
- Severe rash involving reddening, peeling and swelling of the skin that resembles severe burns (Lyells syndrome) or severe rash, blisters, or red patches on the skin (Stevens-Johnson syndrome)
- Bleeding on the brain (sudden severe headache, fit, changes in vision, speaking, understanding or coordination, weakness in an arm or leg)
Stomach ulcers or bleeding which can be severe (you may develop bloody or black tarry stools, severe stomach pain and vomit blood), stomach irritation
(mild stomach pain, heartburn, feeling or being sick, and diarrhoea) and inflammation of the liver
- Salicylism - if you take large doses for a long time you may develop symptoms of salicylism, these include: dizziness, ringing or buzzing in the ear, deafness, sweating, feeling or being sick, headache and confusion.
- Hepatitis (inflammation of the liver causing yellowing of the skin or eyes or tiredness, pain in abdomen, joint or muscles)
Tell your doctor if you notice any of the following side effects or notice any other effects not listed:
Common: may affect up to 1 in 10 people
- Increase in the number of nose bleeds, longer bleeding time or notice that you bruise more easily or have more infections talk to your doctor.
- Indigestion
Uncommon: may affect up to 1 in 100 people
- Runny nose
- Itchy skin rash caused by allergic reaction- pale or red irregular raised patches with severe itching (hives)
Rare: may affect up to 1 in 1,000 people
- Anaemia, changes in numbers and types of blood cells and enzymes seen in blood tests • Difficulty breathing or wheezing, worsening of asthma
- Heavy periods
- Irregular red patches on the skin of the hands and arms (erythema multiforme)
- Disorder characterised by blood spots, bruising and discolouring to skin (Purpura)
- Bleeding in the skin, mucous membranes
- Red tender lumps developing under the skin (Erythema nodosum)
Not known: frequency cannot be estimated from the available data
- Hyperuricemia (high levels of uric acid in the blood)- causing crystals to deposit in joints of hands/feet causing pain (Gout)
- Nosebleeds, bleeding of the gums, which may be prolonged. (Please advise doctor or dentist if surgery is planned)
- Reduction of red blood cells which can make the skin pale and cause weakness or breathlessness (anaemia), Reduction in red blood cells which cause pale yellow skin and weakness or breathlessness (haemolytic anaemia), blood disorder resulting in impaired blood clotting leading to an increased risk of bleeding, reduced number in red and white blood cells, blood loss, elevated blood enzymes levels (as seen in blood test)
- Headache
- Feeling of dizziness or spinning
- Hearing loss, Ringing or buzzing in the ears
- Liver problems
- Reduced kidney function
- Acute myocardial ischemia (painful heart condition caused by lack of blood flow to the heart) with or without myocardial infarction (heart attack) occurring as part of an allergic reaction (Kounis syndrome).
Additional side effects in children
Aspirin may be associated with the development of a condition called Reye’s Syndrome, which causes severe liver and brain damage.
Reporting of side effects
If you get any side, talk to your doctor or pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via Yellow Card Scheme Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.
5. How to store Aspirin 300mg Tablets
- Keep this medicine out of the sight and reach of children.
- Do not use this medicine after the expiry date which is stated on the carton. The expiry date refers to the last date of that month.
- Do not store above 25°C. Store in the original container and keep the container tightly closed.
- Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
6. Further Information
What Aspirin 300mg Tablets contain
Each tablet contains Aspirin 300 mg as the active ingredient. The tablets also contain Lactose and maize starch.
What Aspirin Tablets 300mg look like and contents of the pack
The pack contains white round biconvex tablets. The tablets are available in blister packs of 16 or 20 tablets and packs of 25 tablets. Packs of 50, 100, 500 and 1000 tablets are available on prescription only. Not all pack sizes may be marketed.
Marketing Authorisation Holder:
Bristol Laboratories Ltd.,
Unit 3, Canalside, Northbridge Road,
Berkhamsted, Hertfordshire
HP4 1EG, United Kingdom.
Telephone: 0044 (0) 1442 200922
Email: info@bristol-labs.co.uk
Aspirin 300mg Tablets BP; PL 17907/0445
The leaflet was last revised in August 2026.
To request a copy of this leaflet in Braille, large print or audio format, please contact the licence holder at the address above (telephone or email).