Amoxicillin at a glance
Medicine class
Broad-spectrum penicillin antibiotic (beta-lactam).
Available forms
Capsules, tablets, oral suspensions and hospital-administered injection or infusion.
Food
Oral amoxicillin can be taken with or without food.
Prescription status
Available only on prescription in the UK.
What is Amoxicillin used for?
Licensed uses include susceptible bacterial infections selected according to infection site, severity, likely organism and antimicrobial susceptibility.
Ear, nose and throat infections, including bacterial sinusitis, acute otitis media and streptococcal tonsillitis or pharyngitis.
Lower respiratory infections, including community-acquired pneumonia and acute exacerbations of chronic bronchitis.
Urinary infections, including acute cystitis, acute pyelonephritis and asymptomatic bacteriuria in pregnancy.
Dental abscess with spreading cellulitis.
Lyme disease, typhoid or paratyphoid fever, and prosthetic joint infection.
Helicobacter pylori eradication as part of combination treatment.
Prevention of endocarditis in selected circumstances.
Injectable amoxicillin is also licensed for endocarditis treatment, bacterial meningitis and bacteraemia associated with listed infections.
How does Amoxicillin work?
Amoxicillin blocks production of peptidoglycan, an essential part of the bacterial cell wall. This kills susceptible bacteria; resistant or beta-lactamase-producing bacteria may not respond.
Amoxicillin preparations and strengths
Capsule
Route: Oral
Strengths: 250 mg, 500 mg
Oral suspension
Route: Oral
Strengths: 125 mg/5 mL, 250 mg/5 mL, 500 mg/5 mL
How to take Amoxicillin
Follow the dispensing label and product leaflet. Oral amoxicillin may be taken with or without food. Swallow capsules or tablets with water; do not open capsules, and take the selected film-coated tablets unchewed. Shake liquid well and measure it with the supplied oral syringe or medicine spoon, not a kitchen teaspoon. Follow the pharmacy label for storage because reconstituted suspension requirements vary by product.
Check that the liquid strength matches the prescription.
Use only the measuring device supplied or recommended by a pharmacist.
Injection and infusion preparations are administered by healthcare professionals.
Amoxicillin side effects
Common or expected effects
- Diarrhoea
- Feeling sick (nausea)
- Skin rash
Get urgent medical advice
- Sudden facial, mouth or throat swelling, breathing difficulty, collapse or severe dizziness
- Blistering, peeling or widespread rash, particularly with fever
- Severe or bloody diarrhoea, with or without abdominal cramps
- Yellow skin or eyes, dark urine or pale stools
- Unusual bruising, bleeding or marked skin-colour changes
- Persistent vomiting with abdominal pain, lethargy, pallor or low blood pressure
Amoxicillin in pregnancy
Amoxicillin can be used during pregnancy when recommended by a clinician. UK pregnancy information reports no concern that penicillin antibiotics harm the baby, and exposure alone does not normally require additional monitoring for major birth defects beyond routine antenatal care.
Amoxicillin while breastfeeding
Amoxicillin is generally compatible with breastfeeding because only small or negligible quantities enter milk. For a full-term, healthy infant, monitor for diarrhoea, vomiting, oral thrush, rash, breathing problems, unusual sleepiness or poor feeding. Seek specialist advice for premature or unwell infants.
Amoxicillin interactions
Tell the prescriber or pharmacist about all prescription, over-the-counter and complementary medicines. Important examples include:
Methotrexate
Penicillins can reduce its renal clearance and increase toxicity risk; clinical review and monitoring may be needed.
Warfarin and other oral anticoagulants
Anticoagulant effect and INR may change, so additional clotting monitoring may be required when amoxicillin is started or stopped.
Common questions about Amoxicillin
Answers are fully visible for fast scanning and source review.
Does amoxicillin treat colds or flu?
No. It treats susceptible bacteria, not viral infections such as colds or flu.
Can I take amoxicillin if I have a penicillin allergy?
Do not take it if you have a confirmed penicillin allergy. A previous severe immediate reaction to another beta-lactam antibiotic is also a contraindication; clarify uncertain allergy histories with a clinician.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.