Amoxicillin and Clavulanate (Oral)

Amoxicillin is a penicillin based antibiotic and clavulanate potassium is a beta-lactamase inhibitor. When used in combination, these medicines are a powerful treatment for bacterial infections with very few side effects.


Amoxicillin and clavulanate, when taken in combination, function as a powerful antibiotic. This combination of medications is commonly prescribed under the brand name Augmentin in the United States and is one of the most effective and prolifically used antibiotics in modern medicine. It has very few side effects, is generally tolerated very well and is relatively inexpensive.

Amoxicillin was developed in the 1960s as a semi-synthetic derivative of 6-aminopenicillanic acid (6-APA). It was one of several variations of penicillin derived in the early 1960s and was approved and introduced to the public in 1972.

Clavulanate is the potassium salt form of clavulanic acid. This acid was discovered in 1974 and is derived from the amino acid arginine. It is similar in structure to a penicillin, but its mechanism of action is different. Clavulanate is not effective as an antibiotic agent on its own. It binds to the beta-lactamase enzyme, acting as an inhibitor. This function helps prevent bacterial resistance to the antibiotic effects of amoxicillin in bacteria that have developed resistant qualities.

Because it has so few side effects and very few of those are dangerous, amoxicillin and clavulanate in combination is used to treat a wide range of bacterial infections. It also comes in a variety of delivery forms and dosage strengths, so it can be used by different age groups, races and genders with great efficacy. Amoxicillin and clavulanate are not effective in treating viral infections such as influenza, colds or stomach viruses. The overuse of antibiotics in addressing viral infections has led to the rise in bacterial strains that are resistant to antibiotics, particularly those in the penicillin family, such as amoxicillin.

Conditions treated

  • Lower Respiratory Tract Infections
  • Acute Bacterial Otitis Media
  • Sinusitis
  • Cellulitis
  • Urinary Tract Infections
  • Staphylococcus skin infection
  • Acute bacterial infection of the sinuses
  • Bronchitis
  • Chronic bronchitis
  • Infections caused by E.Coli Bacteria
  • Pneumonia
  • Bacterial pneumonia
  • Fever in children
  • Diverticulitis
  • Infection of the foot, particularly related to diabetic complications
  • Biliary tract infection
  • Dog bite wound
  • Cat bite wound
  • Human bite wound
  • Infections in patients with compromised immune systems
  • Presumed infections with unknown cause (elevated white blood cell counts)

Type of medication

  • Combination drug
  • Amoxicillin - penicillin derived antibiotic
  • Clavulanate - beta-lactamase inhibitor

Side effects

Like all medications, amoxicillin and clavulanate (Augmentin) can cause side effects in certain patients. Some of the more common complications experienced by patients are:

With these more common side effects, discontinuation of amoxicillin and clavulanate is not necessarily indicated. The patient could simply endure many of these conditions until the course of the antibiotic has been taken, or treat them with over the counter medications (eg ibuprofen, antidiarrheal medication, etc) to control the symptoms.

Rarely, Augmentin may have more serious side effects that would certainly indicate immediate discontinuation of the medication and perhaps further medical treatment. If Augmentin is discontinued and was prescribed for an infection, then another class of antibiotics would need to prescribed to the patient.

More severe side effects can include:

  • pale or yellow skin
  • severe agitation
  • confusion or weakness
  • strange thoughts or behaviors
  • fever
  • bloody diarrhea
  • severe tingling or numbness
  • watery stool or diarrhea
  • loss of appetite
  • dark colored urine
  • convulsions or seizures
  • easy bruising or bleeding
  • bruising
  • muscular weakness
  • unusual pain
  • severe nausea
  • clay-colored stool
  • jaundice (including yellowing of the skin or whites of the eyes)
  • upper stomach pain

Augmentin may cause a significant skin reaction that causes fever, burning in the eyes, pain, a sore throat and fever, as well as swelling of the face and/or tongue. This response may then be followed by a rash that is either red or purple. This rash will spread quickly and may be concentrated in the face or upper body. The rash will cause blistering and peeling. If patients have this response, they should immediately stop taking Augmentin and seek emergency medical help.

Also, because amoxicillin is derived from the antibiotic penicillin, patients with an allergy to penicillin need to be prescribed Augmentin with care and supervision. The most common response in a penicillin allergy is hives or skin rash. However, depending on the patient's level of sensitivity and exposure to the medication, the reaction can be much more severe, including a life-threatening response called anaphylaxis, which can affect multiple organ systems in the body and be fatal if not treated quickly enough. In most cases where the allergy is known, the bacterial infection should be treated using another class of antibiotics.

On the whole, reported side effects of Augmentin are very low, which is why it is the first line of treatment for many conditions.


For most infections and in most adults, the typical dosage amoxicillin and clavulanate (Augmentin) is one 500 mg tablet taken every 12 hours. It may also be prescribed using 250 mg tablets taken once every eight hours. However, it is important to note that these forms are not interchangeable. Both strengths of the tablet contain 125 mg of clavulanic acid, so taking two of the 250 mg tablets in place of a 500 mg tablet would double the amount of clavulanate ingested by the patient. The same is true of the 250 mg tablet and the 250 mg chewable tablet. Their levels of clavulanate are not the same and so cannot be used interchangeably.

If the patient is fighting a particularly severe infection, particularly of the upper respiratory tract, an adult patient should be prescribed one 875 mg tablet every 12 hours or one 500 mg tablet every eight hours. In situations where the adult has difficulty swallowing pills, the oral suspension can be prescribed instead. In these cases, the 125 mg/5 mL or 250 mg/5 mL suspension can replace the 500 mg tablet. The 200 mg/5 mL suspension or 400 mg/5 mL strength can replace the 875 mg tablets.

Augmentin, regardless of the strength of dosage, is usually prescribed to be taken over a period of 10 to 14 days. This standard practice of treatment has proven effective in eliminating all of the bacteria causing the infection. When patients do not take the entire dose of Augmentin, the infection is often not completely eradicated and will return, often in a more severe form and more resistant to antibiotic treatment. It is critical that patients take the entire prescription, even when their symptoms have abated and they are feeling better. The rise of antibiotic-resistant bacteria has been linked to improper use of antibiotics, including failure to complete the round of treatment.

For children under the age of 12 and/or weighing less than 88 pounds (40 kgs), the recommended dosing for most bacterial infections would be 45 mg every 12 hours or 40 mg every eight hours. This dosage level is indicated for the more common infections such as otitis media, sinusitis, or other respiratory infections. If the infection is less severe, the dosage can be lowered to 25 mg every 12 hours or 20 mgs every eight hours. For pediatric patients, these dosage levels are usually converted to an oral suspension using the 200 mg/125 mg suspension or the 400 mg/125 mg formula.

If the patient weighs more than 88 pounds (40 kg), he or she can take the recommended dose of Augmentin indicated for an adult.

For infants under the age of three months, the indicated dosage would be 30 mg every 12 hours. The standard practice is to use the 125 mg/5 mL oral suspension for infants under 12 weeks.

Augmentin can be taken by patients with kidney or liver impairment and is generally tolerated well at typical recommended dosages. If the impairment is severe, another antibiotic not derived from penicillin may be indicated. Patients who are currently on dialysis should only take 500 mg of amoxicillin and clavulanate per day. Also, Augmentin contains a substance called aspartame and should not be taken by patients with a condition called phenylketonuria.

Amoxicillin and clavulanate should always be taken with food.


Amoxicillin and clavulanate are known to interact negatively with the following medications:

  • probenecid
  • edoxaban
  • heparin
  • rivaroxaban (Xarelto)
  • dabigatran (Pradaxa)
  • apixaban (Eliquis)
  • enoxaparin (Lovenox)
  • allopurinol
  • fondaparinux (Arixtra)
  • warfarin (Coumadin)
  • various oral contraceptives
  • methotrexate
  • cholera vaccine
  • lomitapide
  • lidocaine
  • morphine
  • interferon


Amoxicillin and clavulanate should not be prescribed to anyone with a history of severe reaction to penicillin, beta-lactam substances or those who have shown hypersensitivity to many allergens. Patients with a history of anaphylactic response to known allergens should only be treated with Augmentin under medical supervision until it is known whether or not the patient can tolerate it. Another severe allergic response to Augmentin is a condition called Stevens-Johnson syndrome, a very serious skin infection that requires immediate medical treatment.

Because Augmentin contains aspartame (in the chewable tablets), patients who suffer from phenylketonuria (PKU) should take the medication in tablet form or as an oral suspension, or perhaps be prescribed another class of antibiotic altogether.

Patients who have a history of liver dysfunction, cholestatic jaundice or other serious hepatic condition such as hepatitis should not take Augmentin. While rare, there have been deaths reported due to liver toxicity in association with the use of Augmentin.

Augmentin should not be prescribed for the treatment of mononucleosis as its use has been directly linked to skin rash.

For patients with severe diarrhea, particularly a condition called CDAD, Augmentin is contraindicated. Use of Augmentin (or any antibiotic) can lead to this condition, and so if a patient develops CDAD from taking Augmentin, he or she should be closely monitored and treated with antidiarrheal medication, fluids and electrolytes to guard against dehydration.

Because amoxicillin kills infectious bacteria, it can create an environment where other microbials flourish. This can lead to yeast infections of the mouth and vagina in the patient.

It is absolutely critical that Augmentin is only prescribed to treat a bacterial infection, and that the patient follows the directions of the prescription, without missing a dose or failing to finish the entire course of treatment. Failure to do so can lead to a more severe infection that is resistant to treatment. It should not be taken prophylactically to prevent an infection, nor should it be prescribed in the absence of a diagnosis. Incorrect use of antibiotics makes them less effective for the patient when they are then prescribed later to treat an actual infection. The overprescription of antibiotics, especially in the penicillin family, has led to the evolution of many antibiotic-resistant strains of bacteria, including very dangerous strains of pneumococcal and staphylococcus bacteria that are increasingly difficult to treat and eradicate.

In the event of an overdose, patients should discontinue use of Augmentin and seek medical help. Generally, overdoses do not seem to cause noticeable damage to the patient. However, in severe overdose, or in patients who already have some renal dysfunction, it can result in complete renal failure. Treatment for overdose usually takes the form of medical supervision, increased fluid intake to dilute and eliminate excess medication and discontinuation of the course of treatment.


The combination of amoxicillin and clavulanate (Augmentin) comes in a variety of forms and strengths with different storage requirements.

Augmentin tablets are available in three dosage levels. The 250 mg/125 mg tablets are white ovals. They contain 250 mgs of amoxicillin and 125 mgs of clavulanic acid (potassium salt). These tablets come in bottles with 30 tablets or blister packs of 100 tablets.

The 500 mg/125 mg tablets are also white ovals with 500 mgs of amoxicillin and 125 mgs of clavulanic acid.

These tablets come in bottles of 20 tablets or blister packs of 100 tablets.

The 875 mg/125 mg tablets are white and shaped like a capsule. They are also scored. They contain 875 mgs of amoxicillin and 125 mgs of clavulanic acid. They come in bottles of 20 tablets or blister packs of 100 tablets.

Augmentin is also available in powder form to be mixed into an oral suspension. These mixture comes in several strengths as well.

125 mg/31.25 mg powder per 5 mL in oral suspension. It is a banana flavored powder, and is available in bottles of 75 mL, 100 mL, or 150 mL.

At a strength of 200 mg/ 28.5 mg per 5 mL, this dosage of powder is orange flavored. That is 200 mg of amoxicillin and 28.5 mg of clavulanic acid. It also comes in bottles of 50 mL, 75 mL, and 100 mL.

The 250 mg/62.5 per 5 mL is also an orange flavored powder and comes in bottles of 75 mL, 100 mL, and 150 mL.

The 400 mg/ 57 mg per 5 mL is also an orange flavored powder for oral suspension, containing 400 mg of amoxicillin and 57.0 mg of clavulanic acid as the potassium salt. It comes in 50 mL, 75 mL, and 100 mL bottles.

Augmentin also comes in chewable tablet form.

At 125 mg/ 31.25 mg, the tablets are yellow, round and lemon-lime flavored. These tablets come in cartons of 30 tablets.

The 200 mg/ 28.5 mg tablets are pink and cherry-banana flavored. This strength comes in cartons of 20 tablets.

The 250 mg/62.5 mg chewables are yellow and lemon-lime flavored. These tablets come in cartons of 30.

The 400 mg/57 mg chewable tablets are pink, cherry-banana flavored and round. They come in cartons of 20.

Tablets and the dry powder should be stored at room temperature (below 77 degrees Fahrenheit).

If the Augmentin is dispensed as the reconstituted suspension, it should be refrigerated. After 10 days, the suspension must be disposed.

Keep medication in original container.

Keep medication out of reach of children. If the seal or packaging is broken, do not take medication. Do not dispose of medication by flushing down toilet.


Amoxicillin and clavulanate is a combination medication, commonly marketed as Augmentin (in the United States). Amoxicillin is a derivative of penicillin that has been available since the early 1970s. It is combined with clavulanate, or clavulanic acid, which is a beta-lactamase inhibitor. The combination of these two medications has proved very effective in the treatment of bacterial infections. It is usually indicated for the treatment of sinusitis, middle ear infections, staph infections, various forms of bronchitis and pneumonia, urinary tract infections and other common infections.

Side effects with Augmentin are generally mild and tolerable. They include digestive symptoms such as upset stomach, diarrhea, nausea and vomiting. Side effects may also include hives and other dermatitis reactions. It may also cause headaches and yeast infections. The only serious contraindication in use of Augmentin is for patients who are hypersensitive to derivatives of the penicillin family. Allergic reactions may take the form of serious skin rash, Stevens-Johnson syndrome or anaphylaxis, which may prove fatal.

Augmentin is usually prescribed in doses of 500 mg taken twice daily for a period of 10-14 days. It is very important that the patient take the entire course of treatment.

Amoxicillin and clavulanate do not treat viral infections and should only be prescribed for the treatment of bacterial infection. The prolific use of this and other antibiotics has significant consequences for the individual patient and public health, as it has led to the rise of antibiotic-resistant bacteria that are becoming more and more difficult to treat and eradicate.

Last Reviewed:
December 23, 2017
Last Updated:
April 05, 2018
Content Source: