Amoxicillin 875 mg is a higher-strength antibiotic tablet prescribed for bacterial infections of the respiratory tract, sinuses, ears, skin, and urinary tract. It’s typically taken once every 12 hours, making it a twice-daily option that simplifies treatment compared to lower doses taken three times a day. This is one of the most commonly prescribed antibiotics in the United States, and the 875 mg strength is reserved for more severe infections or for treating certain areas of the body where a stronger dose is needed.
Infections Treated With the 875 mg Dose
Not every infection calls for the 875 mg tablet. The FDA-approved labeling specifies this strength for three main scenarios: severe ear, nose, and throat infections; severe skin infections; and mild to moderate lower respiratory tract infections like bacterial bronchitis or pneumonia. Less severe versions of these same infections are often treated with 500 mg or 250 mg instead.
In practice, the 875 mg dose is frequently prescribed for sinus infections that haven’t responded to watchful waiting, strep throat with significant symptoms, middle ear infections in adults, bacterial pneumonia, and skin infections caused by susceptible bacteria. It also plays a role in treating stomach ulcers caused by H. pylori bacteria, where it’s used alongside other medications to eradicate the infection.
Amoxicillin at various doses also treats urinary tract infections and certain sexually transmitted infections, though the 875 mg tablet isn’t specifically indicated for those conditions in the FDA labeling. Your prescriber may still choose it based on the severity of your infection and your body weight.
How It Works Against Bacteria
Amoxicillin belongs to the penicillin family of antibiotics. It kills bacteria rather than simply slowing their growth, which makes it what pharmacologists call “bactericidal.” It works by blocking a critical step in building bacterial cell walls. Without intact walls, the bacteria essentially burst open and die. This is why amoxicillin works well against actively growing infections but has no effect on viruses, which don’t have cell walls.
One important limitation: some bacteria produce enzymes that break down amoxicillin before it can work. These resistant strains won’t respond to amoxicillin alone. When resistance is suspected, your prescriber may pair amoxicillin with clavulanic acid (a combination product) or choose a different antibiotic entirely.
How to Take the 875 mg Tablet
The standard regimen is one 875 mg tablet every 12 hours. Treatment length varies by infection. Sinus infections and strep throat courses typically run 7 to 14 days, while skin infections may be shorter. The most important thing is completing the full prescribed course, even if you feel better within a few days.
The 875 mg tablet has been studied when taken at the start of a light meal. While amoxicillin in other forms can be taken without regard to food, taking the 875 mg tablet with a small meal is reasonable, particularly if you’re prone to stomach upset. Food does not significantly reduce absorption.
This dose is intended for adults and children weighing at least 40 kilograms (about 88 pounds). Children under that weight threshold use liquid formulations or smaller tablets dosed by body weight. People with significant kidney impairment should not take the 875 mg tablet, as their bodies clear the drug more slowly, which can lead to buildup. In those cases, a lower dose at the same frequency is used instead.
Common Side Effects
Amoxicillin is generally well tolerated. Diarrhea is the most frequently reported side effect, occurring in roughly 2% of people taking amoxicillin alone. That rate jumps to about 10% when amoxicillin is combined with clavulanic acid, so if you’re taking the combination product, loose stools are considerably more likely.
Yeast infections (candidiasis) are another recognized side effect. A meta-analysis of placebo-controlled trials found that amoxicillin increased the risk of yeast infections roughly eightfold compared to placebo, though the overall incidence remains relatively low. Approximately 1 in 27 courses of treatment leads to a yeast infection. Nausea, rashes, and vomiting have not been shown to occur at significantly higher rates than placebo in controlled trials, despite being commonly listed on drug labels.
Penicillin Allergy and Amoxicillin
Because amoxicillin is a penicillin-type antibiotic, anyone with a true penicillin allergy should not take it. That said, the label of “penicillin allergy” is far more common than actual allergy. More than 95% of people who carry this label can tolerate penicillin after proper evaluation. Many people were labeled allergic as children based on a rash that was likely caused by a viral illness, not the antibiotic itself.
If you’ve been told you’re allergic to penicillin and need amoxicillin for an infection, allergy testing can clarify whether you truly react to the drug. This is worth pursuing because avoiding penicillin-type antibiotics unnecessarily often means using alternatives that are less effective, more expensive, or carry more side effects.
Interactions With Other Medications
If you take a blood thinner like warfarin, amoxicillin deserves extra caution. Although some references state that amoxicillin doesn’t directly interact with warfarin, clinical reports tell a different story. Cases of elevated bleeding risk have been documented anywhere from 7 days after starting amoxicillin to 9 days after finishing it. High doses carry the greatest risk: in one study, nearly 86% of patients on high-dose amoxicillin with clavulanic acid experienced dangerously elevated clotting times when also taking warfarin. If you’re on a blood thinner and prescribed amoxicillin, your provider will likely monitor your clotting levels more closely during and shortly after the antibiotic course.
Amoxicillin can also increase the effects of methotrexate, a drug used for autoimmune conditions and certain cancers, by slowing how quickly the kidneys clear it. Let your prescriber know about all medications you’re taking before starting amoxicillin, particularly immunosuppressants and blood thinners.