Amoxicillin and Clavulanic Acid: uses, dosing, side effects
Last updated September 7, 2026.
**Amoxicillin and clavulanic acid (sold as Augmentin) is a prescription penicillin-class antibiotic that pairs amoxicillin with clavulanate potassium, a beta-lactamase inhibitor.** Amoxicillin kills bacteria by breaking down the wall they build around themselves, and clavulanate blocks the enzyme that many bacteria use to destroy amoxicillin, so the pair works against bugs that plain amoxicillin no longer covers. It only works on bacteria, so it does nothing for colds, flu, COVID, or most sore throats and chest colds. The single most important safety point is that a past reaction of hives, facial or throat swelling, or trouble breathing after any penicillin, and any past episode of jaundice or liver trouble after taking this specific combination, both rule the drug out.
What does it treat?
Doctors reach for amoxicillin and clavulanic acid when an infection is likely caused by bacteria that produce beta-lactamase, which makes it a first choice for acute bacterial sinusitis that has dragged on past ten days or got better and then clearly worsened, for middle ear infections in children, and for animal and human bite wounds. The FDA label also covers lower respiratory tract infections including community-acquired pneumonia and bacterial flare-ups of chronic bronchitis, skin and skin structure infections such as cellulitis and abscesses, and urinary tract infections including pyelonephritis. Typical patterns that push a clinician toward this drug rather than plain amoxicillin include facial pressure with thick colored discharge and fever after a week and a half of symptoms, a productive cough with fever in someone with COPD, a red spreading warm patch of skin, or a cat bite on the hand. It is sold as Augmentin and Augmentin XR and as generic amoxicillin and clavulanate potassium tablets, chewable tablets, and oral suspension; the fixed combination itself is the only common combination product, so there is no separate add-on to buy.
How do you take it?
It comes as immediate-release tablets of 250/125 mg, 500/125 mg, and 875/125 mg, as chewable tablets, as oral suspensions including 250/62.5 mg and 400/57 mg and 600/42.9 mg per 5 mL, and as an extended-release 1000/62.5 mg tablet. For adults and children weighing 40 kg or more, the label gives 500 mg every 12 hours or 250 mg every 8 hours for milder infections, and 875 mg every 12 hours or 500 mg every 8 hours for severe infections and respiratory tract infections, which puts the standard ceiling at 875/125 mg twice a day or 500/125 mg three times a day. Two 250 mg tablets are not the same as one 500 mg tablet, because each tablet carries 125 mg of clavulanate, so never substitute them. The extended-release form is dosed as two 1000/62.5 mg tablets every 12 hours for 7 to 10 days for sinusitis or pneumonia, and it is not for anyone with a creatinine clearance under 30 mL/min or on hemodialysis; the 875 mg tablet is also off limits at that kidney function. Take every dose at the start of a meal or a snack, which cuts stomach upset and helps your body absorb the clavulanate. Shake the suspension well, measure it with the dosing syringe rather than a kitchen spoon, and keep it refrigerated. If you miss a dose, take it when you remember, unless your next dose is close, in which case skip the missed one and never double up. Finish the whole course even after you feel better, but stop the drug and call your doctor for a rash or hives, watery or bloody diarrhea, or yellowing of your eyes, and call if you are not improving after 48 to 72 hours.
Side effects to know
- Common: Diarrhea, loose stools, nausea, stomach cramps, and vaginal yeast infections are the usual complaints, and taking each dose with food and finishing the course is often enough to get through them.
- Serious: Stop the drug and get help right away for hives, swelling of the lips, tongue, or throat, wheezing, or trouble breathing, and for a rash that blisters, peels, or involves the eyes or mouth, which can signal Stevens-Johnson syndrome or DRESS. Also stop and call the same day for yellow eyes or skin, dark urine, or right upper belly pain, which point to the cholestatic liver injury this combination is known for, or for severe watery or bloody diarrhea with cramping and fever, which can be Clostridioides difficile colitis and can start weeks after the last dose.
Who should not take it?
Do not take this drug if you have ever had a serious allergic reaction such as anaphylaxis or a severe skin reaction to any penicillin or cephalosporin, or if you have ever had jaundice or liver dysfunction after taking amoxicillin and clavulanate before. Talk to your doctor first if you have reduced kidney function, since doses need adjusting below 30 mL/min, or liver disease, which calls for monitoring, and if you have mononucleosis, because a widespread rash is common in that setting and the label advises against using it. Tell your prescriber about allopurinol, which raises the chance of a rash, probenecid, which the label says should not be given together, warfarin, which can push your INR up, methotrexate, whose levels can rise, and mycophenolate, whose levels can fall; oral contraceptives may work less reliably, so use a backup method during the course. Published data over decades have not identified a drug-related risk of major birth defects in pregnancy, and amoxicillin and clavulanate pass into breast milk in low amounts, so both are usually acceptable when the infection warrants treatment, but confirm with your own doctor. Alcohol does not react with this antibiotic the way it does with metronidazole, so a drink is not dangerous, though it adds to the nausea, loose stools, and dehydration you may already have.
When is it an emergency?
Call 911 if you collapse, have trouble breathing or swallowing, or your lips, tongue, or throat swell after a dose, since anaphylaxis to a penicillin can move within minutes and needs epinephrine, not a phone call to the pharmacy. For a suspected overdose, whether a child got into the bottle or you doubled up badly, call Poison Control at 1-800-222-1222 right away; large amounts mainly cause vomiting, severe diarrhea, and dehydration, and can crystallize in the kidneys and shut down urine output, so drink fluids while you call. Go to an emergency department or urgent care the same day for a rash that blisters or peels, for yellow eyes with dark urine and belly pain, for severe or bloody diarrhea with fever, for a skin infection whose red border is spreading by the hour despite treatment, or for a decrease in how much you are urinating. Seizures are possible at very high doses in people with poor kidney function and are an emergency.
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Common questions
What is the maximum dose I can take in a day?
For adults and anyone over 40 kg, the immediate-release ceiling on the label is 875/125 mg every 12 hours, or 500/125 mg every 8 hours for a three times daily schedule. That works out to no more than 1,750 mg of amoxicillin a day on the twice daily plan and 1,500 mg a day on the three times daily plan. The extended-release form is different and is dosed as two 1000/62.5 mg tablets every 12 hours for 7 to 10 days. Never combine forms or add an extra tablet to make up a dose, because every tablet carries clavulanate and too much of that is what drives the diarrhea and liver problems. If your kidney function is reduced, your prescriber will lower the dose or stretch the interval.
Can I drink alcohol while taking it?
Alcohol does not cause the flushing and vomiting reaction that some antibiotics like metronidazole do, and the label lists no interaction. A drink will not make the antibiotic stop working. The practical problem is that this drug already causes nausea and loose stools in a lot of people, and alcohol adds to both while also dehydrating you when you are fighting an infection. If you are on the drug for a serious infection or feeling rough, it is worth skipping alcohol until you finish the course.
Do I have to take it with food?
Yes, take every dose at the start of a meal or at least a solid snack. Food cuts down the stomach upset and diarrhea that this combination is known for, and it improves how well your body absorbs the clavulanate part. The extended-release tablets specifically must be taken with food, because absorption drops when the stomach is empty. If you use the oral suspension, shake it hard before each dose and measure with the syringe or cup from the pharmacy, and keep the bottle in the refrigerator.
Is it safe during pregnancy or while breastfeeding?
Published data collected over several decades have not identified a drug-related risk of major birth defects or miscarriage with amoxicillin and clavulanate, and it is one of the antibiotics commonly used in pregnancy for infections that need treating. Both amoxicillin and clavulanate pass into breast milk in low amounts, and nursing is generally continued during a course. Watch a breastfed baby for loose stools, thrush, or a rash and mention it to the pediatrician. Tell your prescriber that you are pregnant or nursing so the choice and dose can be confirmed for your situation.
What are the signs of taking too much?
Overdose mainly shows up as vomiting, severe diarrhea, and stomach pain, with dehydration on top. Large amounts can also crystallize in the kidneys and cause pain in your side or a drop in how much you are urinating, and seizures can occur at very high doses, particularly in people with poor kidney function. Call Poison Control at 1-800-222-1222 for any suspected overdose, including a child who got into the bottle, and keep drinking fluids while you call. Call 911 instead if the person is confused, seizing, unresponsive, or having trouble breathing.
What other medicines interact with it?
Probenecid should not be taken with it, because it raises amoxicillin levels in the blood. Allopurinol taken alongside it raises the chance of a skin rash. Warfarin levels can be pushed up, so your INR may need checking more often, and methotrexate can build up while mycophenolate levels can drop. Oral contraceptives may become less reliable during the course, so use a backup method. Tell whoever draws your labs that you are on this drug, since it can cause a false positive urine glucose test with copper reduction methods and can interfere with the galactomannan fungal test.