The usual adult dose is 500-875mg twice daily (every 12 hours) or 250 mg three times daily (every 8 hours).

This medication is a combination of amoxicillin and clavulanic acid. Amoxicillin is an antibiotic medication that kills various bacteria. It works by inhibiting the synthesis of one of the building blocks needed for the bacteria to make it's cell wall. This results in a cell wall that is defective and more likely to rupture.
Resistance to amoxicillin develops when the bacteria are able to produce enzymes that break down the antibiotic. Clavulanic acid works by stopping these enzymes, which allows the amoxicillin to kill the resistant bacteria. The effectiveness depends on factors such as dose, concentration in the blood as well as other body fluids and tissue, and susceptibility of the organism. This medication will only kill certain types of bacteria sensitive to it amoxicillin's antibiotic action. Infections caused by bacteria that are not sensitive to amoxicillin will not show improvement after taking this medication.

Along with its needed effects, Amoxicillin/Clav may cause some unwanted or undesirable effects. Generally, Amoxicillin/Clav is well tolerated and many people will not experience unwanted effects. The frequency and severity of these effects is dependant on many factors including dose, duration of therapy and individual susceptibility. Possible unwanted effects include:

• diarrhea
• nausea
• vomiting
• abdominal cramps
• constipation
• gas
• allergy (e.g. hives, itching, rash, difficulty breathing)
• acid stomach
• headache
• appetite loss
• bad taste

Rare:

• allergy
• swollen tongue and mouth
• pseudomembranous colitis (inflammation of the colon caused by the overgrowth and toxin production of certain bacteria, causing diarrhea)
• jaundice (yellowing of skin and eyes)

Unwanted effects associated with the stomach should be reported to your pharmacist if they persist or become bothersome. Any uncommon or rare unwanted effects should be reported to your pharmacist immediately.

Allergic reactions can occur with use. People with a history of allergy, asthma, hay fever or hives seem to be more susceptible to these reactions. The reaction can be immediate and severe. Allergic symptoms include wheezing, hives, itching, swelling, spasms in the throat and breathing tubes, joint and muscle pain, difficulty breathing, fever and skin rashes. Nausea and vomiting are not symptoms of an allergic reaction.
Amoxicillin is a semisynthetic penicillin. If you have an allergy to penicillin you should not take Amoxicillin/Clav.
Cephalosporins (e.g. cephalexin, cefaclor) are a distinct group of antibiotics related to penicillins. People allergic to cephalosporins may also be allergic to penicillins. Taking the antibiotic repeatedly or for prolonged periods may result in bacterial or fungal overgrowth which can lead to a second infection. When this occurs the medication may need to be stopped and another antibiotic prescribed to treat the new infection.
Diarrhea often develops while taking Amoxicillin/Clav. This is sometimes caused by an overgrowth of bacteria in the gut that are not killed by the antibiotic. In severe cases, this may be life threatening and would require treatment with other antibiotics. In mild cases, symptoms disappear shortly after the drug is discontinued.
Drug Interactions: It is important to tell your doctor and pharmacist of any prescription or over-the-counter medications you are taking. In some cases, the dose of one or both drugs may need to be altered or another drug may be prescribed. The following drugs or drug classes have been known to interact with Amoxicillin/Clav:

• oral contraceptives (e.g. Triphasil®)
• probenecid (e.g. Benemid®)

Use is not recommended in the following situations: 

• allergy to any member of the penicillin, clavulanic acid or cephalosporin (e.g. cephalexin, cefaclor) group of antibiotics
• history of liver problems associated with Amoxicillin/Clav use
• infectious mononucleosis

Caution is recommended in the following situations:

• liver problems
• kidney problems

Use in pregnancy: Amoxicillin/Clav has been used in pregnant women without evidence of risk to the unborn baby. However, it should not be used during pregnancy unless clearly needed. Consult your doctor or pharmacist if you suspect you are pregnant.

Use while breast-feeding: Amoxicillin/Clav does appear in low concentrations in breastmilk. It is generally considered safe in breast-feeding, however consult your doctor or pharmacist before use