Amoxicillinأموكسيسيلين

Amoxicillin, sold under the brand name Amoxil, is a penicillin-family antibiotic used to treat infections caused by bacteria.

Amoxicillin works by preventing bacteria from building the protective cell wall they need to survive, which kills the bacteria. It's effective against a number of gram-positive and gram-negative bacterial strains, including some Staphylococcus, Streptococcus pneumoniae, E. coli, Neisseria gonorrhoeae, and Haemophilus influenzae. It does not work against viral infections such as flu or the common cold.

• Upper respiratory infections (ear infections, sinusitis, bacterial sore throat/strep throat, tonsillitis)
• Lower respiratory infections (pneumonia, bronchitis)
• Urinary tract infections
• Bacterial skin infections
• As part of combination therapy (with other medicines) for stomach ulcers caused by H. pylori infection
• Prevention of bacterial endocarditis before certain procedures, in people at risk
• Anthrax exposure treatment or prevention
• Symptom treatment in Lyme disease

Common infections, adults

• Mild to moderate: 500 mg every 12 hours, or 250 mg every 8 hours, usually for 10–14 days
• Severe: 875 mg every 12 hours, or 500 mg every 8 hours

Strep throat, adults

• 1 gram once daily for 10 days

H. pylori triple therapy (with clarithromycin and a stomach-acid reducer)

• Amoxicillin 1 gram twice daily, for 14 days, alongside the other prescribed medicines

Endocarditis prevention (before certain procedures)

• A single 2-gram dose, 30–60 minutes before the procedure

Other regimens your doctor may prescribe

• Anthrax exposure: 500 mg three times daily (duration set by a doctor)
• Lyme disease: 500 mg three times daily for 3–4 weeks

See the special-populations section below for children's weight-based dosing.

This is educational background, not an individual prescription — your own doctor sets your exact dose and course length. Always complete the full prescribed course, even if you feel better early.

• Can be taken with or before food
• Try to take it at the same times each day — every 8 hours for 3-times-daily dosing, or every 12 hours for twice-daily dosing
• Swallow tablets and capsules whole — do not break, crush, or chew them
• Chew chewable tablets thoroughly before swallowing
• Shake the oral suspension well before each dose, and measure it with the cup provided, not a household spoon
• The suspension can be mixed with water, milk, or fruit juice
• Complete the full course your doctor prescribed, even if you start feeling better — stopping early risks the infection coming back
• Do not share this medicine with anyone else

Take the missed dose as soon as remembered, unless it is almost time for the next dose — in that case, skip the missed dose and resume the normal schedule. Do not take a double dose.

• Tablets and capsules: store in an airtight container at room temperature, away from light, heat, and moisture
• Oral suspension: refrigerate or keep at room temperature according to the specific product's label

• Nausea
• Vomiting
• Diarrhea
• Mild rash
• Headache
• Vaginal irritation or yeast infection

Rare but serious skin reactions have been reported, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and erythema multiforme. Stop the medicine and seek medical attention immediately for redness, peeling, blistering, or a widespread red or purple rash.

Amoxicillin can cause serious allergic reactions, including anaphylaxis, especially in people with a penicillin, cephalosporin, or related-antibiotic allergy. Seek medical attention immediately for rash, hives, difficulty breathing, wheezing, or swelling of the face or throat.

Amoxicillin, like other antibiotics, can allow a harmful bacteria called C. difficile to overgrow in the gut, causing diarrhea that can range from mild to a serious, life-threatening colitis. This can start during treatment or as late as two months or more after the last dose.

Seek medical attention immediately for watery or bloody diarrhea, severe or persistent stomach pain, or persistent nausea and vomiting — even if it appears weeks or months after finishing the medicine.

• Known hypersensitivity to amoxicillin or any component of the product
• A history of a serious hypersensitivity reaction (such as anaphylaxis or Stevens-Johnson syndrome) to penicillin, cephalosporin, or imipenem antibiotics

• Oral contraceptives — amoxicillin may reduce their effectiveness; use an additional method of contraception
• Warfarin (a blood thinner) — may need closer monitoring
• Methotrexate — amoxicillin can raise its blood levels
• Allopurinol — combined use is associated with a higher chance of skin rash
• Probenecid — raises amoxicillin blood levels
• Tetracycline-family antibiotics (such as minocycline or demeclocycline) — may reduce amoxicillin's effectiveness
• Mycophenolate (an immune-suppressing medicine) — amoxicillin can lower its blood levels
• Probiotic supplements — amoxicillin can reduce their effectiveness; consider timing doses apart
• Recent live vaccines — amoxicillin may reduce their effectiveness

Always tell your doctor and pharmacist about every other medicine you take.

Extended-release tablets are not recommended when GFR is below 30 mL/min.

Under 3 months

• Up to about 30 mg/kg per day, divided into 2 doses — under a doctor's care

3 months and older, under 40 kg

• Mild to moderate infection: 25 mg/kg/day every 12 hours, or 20 mg/kg/day every 8 hours
• Severe infection: 45 mg/kg/day every 12 hours, or 40 mg/kg/day every 8 hours
• Usual duration: 10–14 days

Ear infections (acute otitis media), 6 months–12 years

• 80–90 mg/kg/day, divided into 2 doses
• Duration: 10 days for severe symptoms under age 2; 5–7 days for mild-to-moderate symptoms age 2 and older

Strep throat

• 50 mg/kg once daily for 10 days, up to a maximum of 1 gram per day

40 kg and above

• Adult dosing applies

Extended-release tablets have not been shown to be safe and effective in children under 12. Chewable tablets contain phenylalanine — a caution for children with phenylketonuria.

This is educational background, not an individual prescription — a doctor calculates the exact weight-based dose.

Amoxicillin is generally considered one of the safer antibiotics during pregnancy and is generally compatible with breastfeeding — it passes into breast milk only in small amounts, unlikely to affect the nursing infant. A doctor should still be consulted before use in either case.

• Use with caution if you have a history of allergies (especially to other antibiotics), asthma, liver or kidney disease, bleeding disorders, or previous antibiotic-associated diarrhea
• Avoid in infectious mononucleosis — it raises the chance of a widespread rash
• Can cause a false-positive result on some urine glucose tests
• May reduce the effectiveness of recently given live vaccines