Amoxicillin clavulanate 875/125 mg is a combination antibiotic used to treat bacterial infections of the sinuses, ears, lungs, skin, and urinary tract. The “875/125” refers to 875 mg of amoxicillin (the antibiotic that kills bacteria) paired with 125 mg of clavulanate potassium (a compound that helps the antibiotic work against resistant bacteria). It’s one of the most commonly prescribed antibiotics and is typically taken twice a day.
Infections This Medication Treats
The 875/125 mg tablet is the standard adult-strength dose prescribed for a range of common bacterial infections. These include acute bacterial sinusitis, middle ear infections, lower respiratory infections like pneumonia and bronchitis, urinary tract infections, and skin or soft tissue infections such as cellulitis or infected wounds. It’s also used for certain dental infections, particularly abscesses where bacteria have become resistant to plain amoxicillin.
This combination works against both gram-positive and gram-negative bacteria, giving it a broader reach than many single-ingredient antibiotics. That breadth is why doctors often choose it when they suspect a mixed infection or when a simpler antibiotic hasn’t cleared the problem.
Why It Contains Two Ingredients
Amoxicillin on its own is a penicillin-type antibiotic. It kills bacteria by breaking apart their cell walls, essentially destroying the structural shell that holds the organism together. The problem is that many bacterial species have evolved a defense: they produce enzymes called beta-lactamases that deactivate amoxicillin before it can do its job.
That’s where clavulanate comes in. Clavulanate has almost no bacteria-killing power by itself, but it binds to those defensive enzymes and shuts them down. With the enzymes neutralized, amoxicillin can reach the bacteria and work as intended. Think of it as a bodyguard that clears the path so the antibiotic can do its work. This pairing effectively extends amoxicillin’s reach to cover bacteria that would otherwise be resistant to it.
How to Take the 875/125 mg Tablet
The standard regimen for adults is one tablet every 12 hours. Taking it at the start of a meal or snack helps reduce stomach upset, which is one of the most common complaints with this medication. You can technically take it without food, but eating something first makes a noticeable difference for most people.
After you swallow a tablet, amoxicillin reaches its peak concentration in your bloodstream in about 2 hours, while clavulanate peaks faster, at roughly 1 hour. The length of a full course varies depending on the infection being treated, but most prescriptions run between 5 and 14 days. Finishing the entire course matters even if you feel better early, because stopping short can allow surviving bacteria to rebound and potentially develop resistance.
Common Side Effects
Gastrointestinal symptoms are by far the most frequent side effects. Diarrhea, nausea, and stomach discomfort are common because the antibiotic doesn’t distinguish perfectly between harmful bacteria and the beneficial bacteria in your gut. The clavulanate component is particularly associated with digestive upset, which is one reason the formulation keeps that ingredient at the lower 125 mg dose.
Some people develop a skin rash, vaginal yeast infections, or mild headaches. These effects are generally temporary and resolve after the course is finished. Eating yogurt or taking a probiotic supplement during treatment may help offset some of the gut-related side effects, though evidence on this varies.
Who Should Not Take It
Two groups of people should avoid this medication entirely. The first is anyone with a history of serious allergic reactions to penicillin, amoxicillin, clavulanate, or related antibiotics like cephalosporins. Serious reactions include anaphylaxis (a life-threatening allergic response) and Stevens-Johnson syndrome (a severe skin reaction). A mild rash from penicillin as a child is a different situation, and your prescriber can help you assess whether the risk applies to you.
The second group is people who have previously experienced liver problems, specifically cholestatic jaundice, while taking this particular combination. The clavulanate component can affect liver function in susceptible individuals, and a prior episode of liver dysfunction linked to this drug is a clear reason to use a different antibiotic instead.
Why Your Doctor Chose This Over Plain Amoxicillin
If you’ve been prescribed the 875/125 combination rather than regular amoxicillin, it usually means your doctor suspects the infection involves bacteria that produce beta-lactamase enzymes. This is increasingly common. Bacteria in sinus infections, skin wounds, and urinary tract infections have steadily developed more resistance to plain penicillin-type drugs over the past several decades. The clavulanate component compensates for that resistance without requiring a jump to a stronger class of antibiotics.
In some cases, doctors prescribe it as a second-line treatment after a course of plain amoxicillin or another antibiotic failed to resolve the infection. The broader coverage makes it a practical next step before considering more specialized options.