Amoxicillin, Clavulanic acid (Augmentin): Uses, Dosage, Side effects, and Abuses
February 05, 201907,648

What is Augmentin?

Augmentin is a combination of two drugs: amoxicillin and clavulanic acid. It is used to treat bacterial infections.1

It is available as tablets, chewable tablets and a powder that you can dissolve in water.1,2

Augmentin is a prescription drug. You can only buy it with a valid order from your doctor.3

How does Augmentin work?

The two drugs in Augmentin work together to kill bacteria.


Amoxicillin is the part of the drug that kills the bacteria.1 It does this by blocking a group of enzymes in the bacteria called transpeptidases.4

Normally, transpeptidases link protein-sugar complexes around the outside of the bacterium. This creates a protective wall that helps keep our body from being able to kill them.4

Amoxicillin keeps the bacteria from building its protective wall. This allows the environment in our bodies to kill it.4

Many bacteria have figured out a way to keep amoxicillin from working. This is called “resistance”.4

Bacteria that are resistant to amoxicillin make another group of enzymes called β-lactamases. β-lactamases cut up the part of amoxicillin that binds the transpeptidase enzymes. Once chopped up, amoxicillin cannot stop the transpeptidase enzymes. The bacteria can make its wall.4

Clavulanic acid

Clavulanic acid is in Augmentin to “re-sensitize” bacteria resistant to amoxicillin.4

Clavulanic acid binds to the β-lactamase enzymes and keeps them from working. This keeps the β-lactamase enzymes from chopping up amoxicillin, so amoxicillin can kill the bacteria.4


Figure 1: How Augmentin works


In a normal bacterium, transpeptidase enzymes (brown) build a protective wall of sugars (purple) and proteins (orange) (a). In non-resistant bacteria, amoxicillin (red) can prevent the transpeptidases from working (b). In resistant bacteria, β-lactamases chop up amoxicillin so it cannot work (c). Adding clavulanic acid (grey) blocks the β-lactamases, so amoxicillin can work (d). (Original diagram. See source 4 for more details.)

Augmentin Usage

The FDA has approved Augmentin to treat infections of the1:

  • Lung
  • Sinuses
  • Middle ear
  • Skin
  • Urinary tract (UTIs)

Augmentin is useful if the infection is being caused by one of the following types of bacteria, if they can make β-lactamase enzymes1:

  • H. influenzea
  • M. catarrhalis
  • E. coli
  • S. aureus
  • Klebseilla
  • Enterobacter

Augmentin Dosage

Adults and Children who weigh over 40 kg

The most common adult dosage of Augmentin is either1:

  • One 500 mg tablet every 12 hours or
  • One 250 mg tablet every 8 hours

If your infection is severe, your doctor may increase your dosage to 1:

  • One 875 mg tablet every 12 hours or
  • One 500 mg tablet every 8 hours

If you have problems swallowing tablets, your doctor may prescribe the Augmentin powder to dissolve in water. The solutions can replace the tablets as follows 1:

  • 500 mg tablet à 125 mg/5 mL or 250 mg/5 mL
  • 875 mg tablet à 200 mg/5 mL or 400 mg/5 mL

Please note that you cannot add the tablet dosages together. Neither can the chewable tablets replace the tablets you swallow whole. This is because they do not contain equal amounts of clavulanic acid.1 (See Warnings for Augmentin Use).

Please follow your prescription exactly.

Children who weigh less than 40 kg

Children who weigh less than 40 kg and are under the age of three months are usually prescribed 30 mg/kg every 12 hours. This is almost always given as the 125 mg/5 mL liquid.1

Children who weigh less than 40 kg, but are older than three months, may be prescribed different dosages depending on the infection they have.1

Common dosages for older children are summarized in Table 1.


Table 1: Common dosages for older children based on infection type (Reference: 1)


Adults with Kidney Disease

Adults (and children who weigh over 40 kg) with severe kidney disease need smaller doses of Augmentin.1

How much smaller your dose may need to be depends on how severe your kidney disease is.1

If your creatinine clearance is 1:

  • Less than 30 mL/min your doctor will likely prescribe either 250 mg or 500 mg of Augmentin every 12 hours
  • Less than 10 mL/min your doctor will likely prescribe either 250 mg or 500 mg of Augmentin every 24 hours

Whether your doctor choses the higher or the lower dosage for you will depend on how severe your infection is.1

Augmentin Side effects

More Common Side effects

The most common side effects of Augmentin are 1:

  • Diarrhea
  • Upset stomach
  • Rash
  • Hives
  • Vomiting
  • Vaginal infection in women

These side effects may occur in up to 9 percent of people taking Augmentin.

Less often, people taking Augmentin may experience these mild side effects 1:

  • Stomach pain
  • Black “hairy” tongue
  • Gas
  • Headache
  • Reversible yellowing of the teeth
  • Dizziness
  • Nervousness
  • Confusion
  • Hyperactivity
  • Insomnia
  • Cloudy urine

Serious Side effects

Though rare, Augmentin can cause serious side effects. These include 1:

  • Severe allergic reactions (see below)
  • Liver failure
  • Kidney failure
  • Blood in urine
  • Blood in stool
  • Anemia
  • Changes in the numbers of white blood cells in the body
  • New infections (see below)
  • Breakdown of muscle
  • Seizures

Allergic Reaction to Augmentin

There is a risk of developing a severe allergy to Augmentin. This reaction is likely due to an immune response to the amoxicillin.1

Doctors know this because people who are allergic to penicillin are more likely to have an allergic reaction to Augmentin.1 Amoxicillin has a similar structure to penicillin. It also works the same way in the body.1,4


Figure 2: Structures of penicillin and amoxicillin.
Identical parts of the molecules are highlighted by a red circle.
(modified from


Symptoms of an allergic reaction to Augmentin may include:

  • A wide-spread rash5
  • Weakness or paleness caused by anemia5
  • Difficulty peeing
  • Back pain from swelling in your kidneys 1,5,6
  • Fever 1,5,6
  • Headache5
  • Nerve pain or numbness (caused by immune reaction in blood vessels cutting of blood flow)5,6
  • Swelling of your face, eyes, tongue or throat5
  • Difficulty breathing5

Symptoms of an allergic reaction can begin within minutes of taking the drug. They may, however, not appear until 1 to 3 weeks later.5

Allergic reactions can be life-threatening. If you have any symptoms of an allergic reaction, please call your doctor immediately.1

If your symptoms are severe, or if you are having trouble breathing, call 911 immediately.

If you know you have an allergy to penicillin or another penicillin-like drug, please let your doctor know. There are other antibiotics that may be safer for you.1

Serious Secondary Infections

There is a risk of getting a serious infection while taking Augmentin.1

Taking an antibiotic not only kills the bacteria causing your infection, but also the normal bacteria that live in and on our bodies.1

These healthy bacteria normally help protect our skin and intestines from dangerous bacteria and fungi. If the healthy bacteria are killed off by antibiotics, dangerous bacteria and fungi can find it easier to infect us.1

One bacterium that often infects people after taking antibiotics is C. difficile.1

This bacterium infects the intestines and can cause severe diarrhea. If left untreated, C. difficile infections can be fatal.1

If you develop diarrhea within 3 months of taking Augmentin, be sure to let your doctor know. She may want to test you for C. difficile.1

There is also a risk that the bacteria you are trying to treat, or some other bacteria in your body, may develop a new resistance if you use Augmentin for a long time. Make sure to tell your doctor if your symptoms are not improving. Your doctor may need to give you a different antibiotic.1

Augmentin Overdose

Taking more than 250 mg/kg of Augmentin can lead to an overdose.1

The biggest concern with an overdose with Augmentin is severe swelling of the kidneys and kidney failure.1

Damage to your kidneys is usually reversible once you stop taking Augmentin.1

There is also a risk of damage to your liver and liver failure.1

You are at greater risk for an overdose with Augmentin if you had kidney or liver disease before starting Augmentin therapy.1

If you think you may have overdosed, you should seek medical attention immediately. Doctors can keep your symptoms under control. They can also “reverse” the overdose by filtering the drug out of your blood.1

Warnings for Augmentin Use

General Warnings

Do not take Augmentin if you know you are allergic to it or other penicillin-like antibiotics.1

Do not take Augmentin if you have a history of liver disease or jaundice.1

Do not mix dosage forms of Augmentin without talking to your doctor. The dosages on the label are based on the amount of amoxicillin in the drug. The amount of clavulanic acid is not always kept the same. This means, if you mix dosage forms, you may take very different amounts of clavulanic acid from what your doctor wanted you to take. Dosages you cannot switch out include 1:

  • Two 250 mg tablets for a 500 mg tablet à you would take double the amount of clavulanic acid
  • One 500 mg tablet for two 250 mg tablets à you would only get half the amount of clavulanic acid
  • Any liquid dosage for the equivalent tablet dosage à you may take up to double the amount of clavulanic acid
  • Any chewable tablet for the equivalent normal tablet à you may take up to double the amount of clavulanic acid
  • Any normal tablet dosage for a chewable tablet or liquid dosage à you make get only half of the clavulanic acid

Dosages that may be substituted include 1:

  • Any liquid dosage for the same dose chewable tablet

Take care to follow the instructions for dissolving the powder form of Augmentin exactly. Even small changes in the amount of water you add can have huge effects on the amount of medication you get with each tablespoon.1

Tell your doctor about any and all other drugs you are taking.

Warnings for Special Groups

Older Individuals

Healthy older adults, generally, do not need lower doses of Augmentin.1

If you have any decrease in kidney or liver function, however, your dosage may need to be adjusted.1

Pregnant Women

Augmentin is a category B pregnancy drug.1

This means that animal studies showed no effect on unborn babies. There have not been enough studies on humans to rule out all risk, however.1,7

Your doctor will decide if the benefits of Augmentin outweigh the risks for you.1

Nursing Women

Augmentin can get into the milk of nursing mothers. Doctors believe giving newborns amoxicillin may make it more likely they will develop an allergy to penicillin.1

Augmentin should only be taken when nursing if necessary.1


Phenylkentonuria (PKU) is a genetic disorder that prevents the body from breaking down phenylalanine (Phe).8

As a result, phenylalanine builds up in the body. This causes changes in liver and brain function.8

Individuals with PKU should be very careful taking Augmentin in some of the liquid or chewable tablet forms. These forms contain aspartame as a sweetener and aspartame contains Phe.1

The amounts of Phe in these Augmentin forms are 1:

  • 2.1 mg of Phe per 200 mg Augmentin chewable tablet
  • 4.2 mg of Phe per 400 mg Augmentin chewable tablet
  • 7 mg of Phe in 5 mL 200 mg/5 mL and 400 mg/5 mL

If you have PKU, you should not take these forms of Augmentin.1

The other forms of Augmentin do not contain Phe.1

Individuals with Liver Disease

If you have a history of liver disease, you should not take Augmentin. This includes a history of hepatitis or cholestatic jaundice.1

Make sure to tell your doctor if you have ever been diagnosed with a liver condition. Your doctor may decide that another antibiotic is safer for you.

Individuals with Kidney Disease

If you have mild kidney disease, your doctor will likely prescribe a normal dosage of Augmentin.1

If you have severe kidney disease, your dosage may need to be reduced. Decreased dosages are prescribed if your creatinine clearance is less than 30 mL/min. Please see “Augmentin Dosage” for details.1

Individuals with Diabetes

If you have diabetes, or your doctor suspects you may have diabetes, you should tell your doctor if you are taking Augmentin.1

This is because the tests that measure the amount of sugar in your urine are not accurate when taking Augmentin. Augmentin causes the test to detect more sugar in your urine than there is. Your doctor could incorrectly diagnose you with diabetes or worsening diabetes if she doesn’t know you are taking Augmentin.1

Augmentin Drug Interactions

Augmentin interacts with several drugs, including.

  • Blood thinners

Augmentin increases the effect of blood thinners when you take them together. This increases your risk of bleeding.1

Some common blood thinners include.9:

§ Warfarin

§ Heparins

§ Xa blockers

§ Vitamin K blockers

§ Direct thrombin blockers

  • Birth Control Pills

Augmentin can decrease your ability to absorb the hormones from birth control pills.1

This means that, even if you are taking your birth control pills as prescribed, you may not be getting enough hormones to prevent ovulation.1

You may be able to become pregnant if you take Augmentin with birth control pills.1

You should use other methods to prevent pregnancy for the rest of any cycle during which you took Augmentin.1

  • Probenecid

Probenecid may make it more difficult for your kidneys to get Augmentin out of your body.1

This can lead to higher levels in your body than normal for the dosage you took.1

High blood levels of Augmentin may put you at greater risk for serious side effects.1

These two drugs should not be taken together if possible.1

  • Allopurinol

Taking allopurinol and Augmentin together increases your risk of getting a rash.1

Augmentin vs. Similar Drugs

Augmentin vs. Amoxicillin

Amoxicillin is one of the active ingredients in Augmentin.1

Without the added clavulanic acid, amoxicillin still works the same way. It has nearly identical uses, side effects, and drug interactions.1,10

There are two major differences between Augmentin and amoxicillin alone 1,10:

1. Amoxicillin alone may be safer for you if you have liver disease.

2. Amoxicillin alone cannot kill resistant bacteria.

The main way your doctor will chose whether to prescribe amoxicillin alone or as part of Augmentin is if the bacterium causing your infection is resistant to amoxicillin or not.1

Augmentin vs. Unasyn

Unasyn is a similar drug to Augmentin.

It contains amoxicillin, like Augmentin. It also contains a β-lactamase inhibitor. In Unasyn, this is a drug called sulbactam, rather than clavulanic acid, but these drugs work the same way. They both allow amoxicillin to kill resistant bacteria.1,11

Unasyn is given as a shot or IV, rather than a tablet, chewable tablet or liquid.1,11 Unasyn may be a better choice for you if you are unable to swallow.

Unasyn is used to treat serious infections with penicillin resistant bacteria. These infections may be in the abdomen, skin or genitals.11

The side effects and drug interactions of these two drugs are nearly identical. Unasyn may cause injection site reactions, though, which Augmentin does not.1,11

Unasyn may be safer for you than Augmentin if you have liver disease.1,11

Augmentin vs. Keflex

Keflex is the brand name for the antibiotic cephalexin. Like amoxicillin, cephalexin works by preventing the bacteria from making their protective wall.1,4,12

Cephalexin belongs to a different class of antibiotics, though, and it has a very different structure.,12 This means it can be safely used in most people who are allergic to amoxicillin, penicillin or similar drugs.13

Cephalexin can be used for the same types of infections as Augmentin, and to treat bone infections.,12

Cephalexin may be safer for you if you have liver disease, but less safe if you have kidney disease.1,12

Cephalexin interacts with the same drugs as Augmentin.1,12 It also interacts with metformin and can cause low blood sugar in people taking this drug.12

Augmentin vs. Cipro

Cipro is a brand name of the antibiotic ciprofloxacin. Unlike amoxicillin or cephalexin, ciprofloxacin does not work by stopping the bacteria from building their protective walls.1,14

Ciprofloxacin works by blocking enzymes that the bacteria need to make and repair DNA. Without DNA, the bacteria die.14

Ciprofloxacin can kill bacteria that are amoxicillin resistant, without adding a second drug. It can be used for the infections that Augmentin can treat. It can also treat bone and intestinal infections, and typhoid fever.1,14

Ciprofloxacin should not be used in children under 1 year of age.1,14

Ciprofloxacin may be less safe for pregnant women, older adults, those with heart or kidney transplants.1,14

Some serious side effects seen with ciprofloxacin, but not Augmentin, include,1,14:

  • Swelling or rupture of tendons
  • Hallucinations
  • Depression
  • Problems swallowing
  • Changes in heartbeat and blood pressure
  • Hearing or vision loss
  • Heart attack

Ciprofloxacin interacts with some drugs that Augmentin does not, including1,14:

  • Theophylline
  • Tinzidine
  • Sulfonylureas
  • Phenytoin
  • H2-receptor antagonists
  • Methotrexate
  • NSAIDs
  • Caffeine
  • Drugs containing metal ions

Which drug is better for you will depend on your medical history, other medications you take and the bacterium involved.

Abuse of Augmentin

The DEA has not classified Augmentin as a controlled substance.2

The risk of abuse with Augmentin is very low.

Augmentin FAQs

  • Who makes Augmentin?

Augmentin is made by a company called Dr. Reddy’s Laboratories, Inc.1,3

  • Is amoxicillin clavulanate the same as amoxicillin? Which is stronger?

Not quite. Amoxicillin is a single drug. Amoxicillin clavulanate combines two drugs.1

The clavulanate makes bacteria that normally cannot be killed by amoxicillin to become sensitive to it.1

Both drugs are equally “strong”, but amoxicillin clavulanate is able to kill a wider variety of bacteria with the same “strength”.1

  • What is the best antibiotic for a sinus infection?

There is no “best antibiotic” for a sinus infection, or any infection. Which antibiotic is right for you will depend on1,4:

§ the bacterium causing your infection

§ where the infection is

§ how severe the infection is

§ other medical conditions you have

§ other drugs you take

  • Can I drink alcohol while taking Augmentin?

There have been no reported interactions between alcohol and Augmentin.1

  • Where can I buy Augmentin?

Augmentin is a prescription drug.3 You should be able to buy it anywhere you can get prescriptions filled.


1. Dr. Reddy’s Laboratories, Inc. Augmentin Prescribing Information.,050575s040s042,050597s047s0…. Accessed September 21, 2017.

2. National Institutes of Health: Dailymed. Augmentin – amoxicillin and clavulanate potassium tablet drug label information. Last updated September 1, 2016. Accessed September 21, 2017.

3. FDA. FDA Approved Drug Products. Accessed September 21, 2017.

4. Walsh C. Molecular mechanisms that confer antibacterial drug resistance. Nature Insight Review Articles. 2000;406(6797):775-781. Doi: 10.1038/35021219.

5. Warrington R, Silviu-Dan F. Drug allergy. Asthma & Clin Immun. 2011;7(Suppl1):S10. Doi: 10.1186/1710-1492-7-S1-S10.

6. Clinic M. Vasculitis Symptoms. Last updated October 8, 2014. Accessed September 21, 2017.

7. US Department of Health and Human Services: Chemical Hazards Emergency medical Management. FDA Pregnancy Categories. Last updated May 29, 2008. Accessed September 21, 2017.

8. de Groot M, Hoeksma M, Blau N, Reijngoud D, van Spronsen F. Pathogenesis of cognitive dysfunction in phenylketonuria: review of hypotheses. Mol .Genet Metab Rep. 2010;99:586-589. Doi: 10.1016/j.ymgme.2009.10.016.

9. Harter K, Levine M, Henderson SO. Anticoagulation Drug Therapy: A Review. West J Emerg Med. 2015;16(1):11-17. Doi: 10.5811/westjem.2014.12.22933.

10. Dr. Reddy’s Laboratories, Inc. Amoxil (Amoxicillin) Prescribing Information.,050754s013s014s017,0507…. Accessed September 22, 2017.

11. Pfizer Roerig. Unasyn (ampicillin sodium/sulbactam sodium) Prescribing Information. Last updated April 2007. Accessed September 22, 2017.

12. Sandoz GmBH . Keflex (cyphalexin) Prescribing Information. Last updated October 2015. Accessed September 22, 2017.

13. Campagna JD, Bond MC, Schabelman E, Hayes BD. The use of cephalosporins in penicillin-allergic patients: a literature review. J Emerg Med. 2012;42(5):612-620. Doi: 10.1016/j.jemermed.2011.05.035.

14. Bayer Healthcare Pharmaceuticals. Cipro (ciprofloxacin hydrochloride) Prescribing Information. Last updated September 2008.,19847s42,19857s49,20780s26,21473…. Accessed September 22, 2017.


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