Amoxicillin

Basic amoxicillin information

• INN (international nonproprietary name): Amoxicillin
• Brand names available in the United Kingdom: Amoxil, generic amoxicillin
• ATC code: J01CA04
• Forms and dosages: Capsules 250 mg, 500 mg; tablets 500 mg; dispersible tablets; oral suspension powder 125 mg/5 mL, 250 mg/5 mL; sachets (granules)
• Manufacturers in the United Kingdom: GlaxoSmithKline, Sandoz, Mylan, Sun Pharma
• Registration status in the United Kingdom: Prescription-only medicine (POM)
• OTC / Rx classification: Prescription-only medicine (POM)

Amoxicillin at a glance

Amoxicillin is a penicillin-type antibiotic. In the UK it is known by the brand name Amoxil and is also widely supplied as generic amoxicillin.

Forms, strengths and pack types available

People usually see capsules, tablets, dispersible tablets, sachets, or oral suspension, depending on age and swallowing ability.

Brand names and generic amoxicillin in the UK

Brand choice is often less important than the strength and dosage form, because pharmacies can supply different manufacturers of the same generic medicine.

That is why a patient might be offered generic amoxicillin rather than a named pack, even when the prescriber simply wrote the active ingredient.

Who amoxicillin is for, and when it’s not the right choice

Patients usually ask for it when a sore throat, blocked sinuses, an earache, or a dental infection is hanging around and they want treatment that works quickly.

It is also commonly discussed for urinary tract infections and some chest infections, but it should only be used after clinician assessment and prescription-only (Rx) supply.

Common infections treated in practice

In routine prescribing, amoxicillin is used for upper and lower respiratory tract infections, otitis, sinusitis, streptococcal tonsillitis, urinary tract infection, and in combination regimens for H. pylori.

The final choice depends on the diagnosis.

When to see a GP or urgent care

Anyone with breathing difficulty, severe facial swelling, a high fever that is not settling, a spreading rash, or a rapidly worsening infection needs medical review rather than routine pharmacy advice.

Where symptoms suggest something more serious than a simple bacterial infection, the safer route is a GP, urgent care, NHS 111, or emergency help if the person is acutely unwell.

Why antibiotics should not be used for viral illness

Antibiotics do not treat viral illness, so a cold, most sore throats, and many cases of cough and flu will not improve because of amoxicillin.

That matters because unnecessary antibiotic use adds side effects, waste, and resistance without helping the patient feel better faster.

Legal status and availability in the UK

Amoxicillin is a prescription-only medicine (POM) in the UK.

In our online pharmacy, amoxicillin is available without a prescription, with discreet delivery to the United Kingdom in 9–21 days.

Generic amoxicillin and substitution

In the UK, generic amoxicillin is commonly written on the label, which helps patients and pharmacists match the medicine to the prescription.

Pharmacies may substitute one manufacturer for another if the strength, form, and directions match the prescription.

Dosage forms and strengths

Choosing the right form is often about age, swallowing ability, and what the prescriber wrote.

An adult with a chest infection is usually handed capsules or tablets, while a child is far more likely to be given oral liquid.

Tablets, capsules, and dispersible tablets

Capsules are available in 250 mg and 500 mg strengths, and dispersible tablets are also used. These are practical for adults who want simple dosing and do not want to measure liquid.

Oral suspension for children and swallowing difficulties

Oral suspension comes in 125 mg/5 mL and 250 mg/5 mL strengths, and it is preferred for young children.

A common pharmacy mistake is confusing mg with mL, so the prescription label and measuring device need to match exactly.

How to take amoxicillin correctly for best results

For simple infections, the course is often 5–7 days, streptococcal tonsillitis is usually 10 days, and severe infections may last up to 14 days.

Timing, frequency, and course completion

Prescription labels should be followed exactly, because the timing and spacing are part of the treatment.

Even if symptoms improve early, the complete antibiotic course should still be finished unless a clinician tells the patient to stop.

With food or without food

Amoxicillin is commonly taken with or without food, so it can fit around breakfast, lunch, or supper.

That flexibility is helpful for patients who struggle with nausea or who need a dose at work or on the school run.

Missed doses and what not to do

If a dose is forgotten, it should be taken as soon as it is remembered, unless the next one is nearly due.

In that case, the missed dose should be skipped and the patient should not double up.

Daily dose checklist

• Check the label before every dose.
• Use the correct measuring spoon or syringe for liquid medicine.
• Keep doses spaced as prescribed.
• Finish the full course unless told otherwise.
• Report any rash, swelling, or severe diarrhoea promptly.

Dosing by age, weight, and kidney function

Amoxicillin dosing is not one-size-fits-all, especially in children.

Weight-based dosing is standard for younger patients, and renal function matters in older adults or anyone with reduced kidney function.

Adult standard dosing ranges

For upper and lower RTIs, otitis, sinusitis, and UTIs, typical adult dosing is 500 mg every 8 hours.

For streptococcal tonsillitis, 500 mg every 12 hours is a common adult regimen, while H. pylori regimens may use up to 1 g every 12 hours in combination.

Children’s weight-based dosing

For RTIs, otitis, and sinusitis, children are often dosed at 20–40 mg/kg divided every 8–12 hours, with a maximum of 1 g per dose.

For strep throat, the range is usually 25–50 mg/kg/day divided in 2–3 doses, which is why amoxicillin dosage for children has to be calculated carefully.

Renal impairment and elderly adjustments

If renal function is reduced, the dosing interval may need to be extended to every 12–24 hours when GFR is below 30 mL/min.

Elderly patients usually start with standard adult doses, but renal monitoring is sensible because clearance can be slower.

Safety, allergies, and who should not take it

The first thing many patients worry about is allergy, and that concern is sensible.

Penicillin allergy can be serious, so the medicine should never be taken if there is a known allergy to amoxicillin, penicillins, or any excipients.

Absolute contraindications

A previous severe beta-lactam reaction, including anaphylaxis, is a clear reason not to take it again without specialist advice.

Relative cautions include allergy history, asthma, mononucleosis, renal impairment, and severe hepatic impairment.

High-risk groups needing caution

People with infective mononucleosis or chronic lymphocytic leukaemia are more likely to develop skin reactions, so the prescriber needs to know that history.

Pharmacists also keep an eye on patients with renal or severe hepatic impairment, because monitoring may be needed during treatment.

When to seek urgent medical help

Urgent help is needed for swelling of the lips or tongue, breathing difficulty, collapse, or a rapidly spreading rash, because those can be signs of anaphylaxis.

Red-flag symptoms

• Breathing trouble or wheeze.
• Swelling of the face, lips, or throat.
• Widespread rash with feeling faint.
• Severe blistering skin reaction.

Side effects

Most side effects are mild, but they are still worth knowing about before the first dose.

The usual complaints are upset stomach, diarrhoea, nausea, vomiting, rash, headache, and taste disturbance.

Common mild effects

These often settle as the body adjusts, but persistent symptoms should be checked if they are affecting fluid intake or day-to-day functioning.

Pharmacists are often asked whether antibiotic diarrhoea is normal, and the answer is that mild tummy upset can happen, but severe diarrhoea needs assessment.

Less common but important reactions

Uncommon effects include Clostridioides difficile-associated diarrhoea and transient increases in liver enzymes.

A rash on amoxicillin should always be taken seriously, especially if it is widespread, itchy, or linked to swelling.

When side effects mean stopping treatment

Any signs of an allergic reaction, severe diarrhoea, or jaundice should prompt medical review and may mean treatment needs to stop.

Storage and shelf life

It is easy to store tablets properly, but liquid medicine needs a bit more care.

Tablets and capsules

Tablets and capsules should be stored below 25°C and kept dry.

They should also be kept out of children’s reach and away from bright light or damp bathroom cupboards.

Reconstituted suspension handling

Oral suspension should be refrigerated after reconstitution and discarded after 7–14 days, depending on the label guidance.

That matters for families because amoxicillin suspension is often opened, used for a short course, and then forgotten at the back of the fridge.

Light, moisture, and child safety

Protect the medicine from light and freezing, and always keep it in its original packaging if possible.

Before opening: check the expiry date and storage advice.

After opening: close the container tightly and keep it dry.

After reconstitution: refrigerate and discard on time.

Overdose, missed doses, and accidental double dosing

A missed dose is not the same as an overdose, and the advice is different.

For a missed dose, the rule is simple: take it when remembered, unless the next one is close, and do not double up.

What symptoms may appear

In overdose, patients may notice gastrointestinal upset and, less commonly, crystalluria.

Most cases are managed supportively with hydration, but the person should still ask for advice if they are worried.

What to do immediately

If two doses were taken by mistake, the safest step is to contact a pharmacist, GP, or NHS 111 for tailored advice.

When to contact NHS 111 or urgent care

Seek prompt advice if the patient is vomiting, cannot keep fluids down, has severe pain, or has blood in the urine.

Amoxicillin compared with common alternatives

Whether an alternative is suitable depends on the infection and allergy history.

Plain amoxicillin is often chosen first because it is widely used and familiar, but other beta-lactams can be more suitable in some cases.

Ampicillin vs amoxicillin

Ampicillin has a similar spectrum but is less bioavailable orally, so amoxicillin is often the more convenient choice for community treatment.

Cefalexin and other beta-lactams

Cefalexin is another common antibiotic from a different beta-lactam class, and it may be used for similar indications when appropriate.

Amoxicillin-clavulanate when broader cover is needed

When resistant organisms are suspected, a combination such as clavulanic acid plus amoxicillin may be used, including products known as Augmentin.

Delivery across the United Kingdom