Amoxicillin

Medically Reviewed By University of Illinois Chicago Drug Information Group

Amoxicillin at a glance

Key highlights to know about amoxicillin are:

  • Amoxicillin is used to treat certain types of bacterial infections, such as those of the ear, nose, throat, urinary tract, skin, and lungs (pneumonia). It is also used for an infection caused by Helicobacter pylori (H. pylori), which causes ulcers.
  • Amoxicillin is available as a capsule, tablet, chewable tablet, or liquid suspension that is taken by mouth.
  • Amoxicillin is typically a low-cost drug, defined as costing less than $30/month.
  • Amoxicillin is available as a generic medication.

Important safety warnings for amoxicillin

Users of amoxicillin should be aware of these safety warnings:

  • Allergic (hypersensitivity or anaphylaxis) warning: Amoxicillin can cause serious and sometimes fatal allergic reactions, most often in those with a history of a penicillin allergy. Tell your doctor if you have an allergy to amoxicillin, penicillin antibiotics, or antibiotics called cephalosporins.
  • Diarrhea warning: A type of diarrhea, called Clostridioides difficile (also called “Clostridium difficile” or “C. diff”)-associated diarrhea, has occurred with use of amoxicillin. Tell your doctor if your diarrhea is severe (watery or bloody stools) or occurs two months or more after stopping amoxicillin.
  • Drug-resistant bacteria warning: Bacteria can become resistant to antibiotics, such as amoxicillin, especially if it is used for something other than a bacterial infection. If this happens, the bacteria may not be treatable by other antibiotics in the future. Resistance is more likely if amoxicillin is not taken exactly as directed by a doctor.
  • Mononucleosis warning: Amoxicillin should not be used to treat a viral infection called mononucleosis (“mono”) because it may increase the risk of a skin rash.
  • Phenylketonuria warning: If you have phenylketonuria (PKU, an inherited condition where a special diet is followed because the body cannot break down the amino acid phenylalanine), it is important to know that some amoxicillin chewable tablets may contain phenylalanine.

Talk with your doctor about these warnings in the context of your individual treatment plan and medical history.

What amoxicillin treats

This medication is used to treat:

  • Bacterial infections, such as infections of the ear, nose, throat, urinary tract, skin, and lower respiratory tract (pneumonia). It is also used for an infection caused by Helicobacter pylori, which causes ulcers.

Doctors sometimes prescribe medications for different uses. Ask your doctor or pharmacist for information about other uses of this medication.

How it works

Amoxicillin is a prescription drug that works like penicillin. It works by stopping bacteria from building their cell walls to grow and survive, which kills the bacteria. Amoxicillin works against many types of bacteria.

Amoxicillin comes in many forms that are administered by mouth, including capsules, tablets, chewable tablets, and liquid suspension. All forms of amoxicillin are available as a generic.

Side effects of amoxicillin

Amoxicillin side effects are possible and may go away with continued use. Serious side effects are rare.

Common side effects

The more common side effects that occur with amoxicillin include:

  • Diarrhea
  • Nausea
  • Perversion in taste (change in taste)
  • Rash
  • Vomiting

Serious side effects

Call your doctor right away if you have serious side effects. Seek emergency care (call 911) if you experience life-threatening symptoms, such as difficulty breathing; chest pain; loss of consciousness; sudden vision changes; or swelling of the face, mouth, tongue or throat.

Serious side effects and their symptoms can include the following:

  • Allergic reaction (hypersensitivity or anaphylaxis). Symptoms can include:
    • Breathing problems
    • Difficulty swallowing
    • Hives
    • Itching
    • Rash
    • Skin peeling
    • Swelling of your face, mouth, tongue, throat, lips or eyes
    • Wheezing
  • Severe diarrhea. Symptoms can include:
    • Bloody stools
    • Fever
    • Stomach cramps
    • Watery stools

Other side effects are possible. Talk to your doctor or pharmacist if you have any side effect that bothers you or that does not go away.

Costs of amoxicillin

Without insurance, amoxicillin is typically a low-cost drug (defined as costing less than $30/month). All forms of amoxicillin are available as generic drugs. You can check the out-of-pocket cash pay price for amoxicillin on prescription drug discount websites.

How amoxicillin may interact with other medicines

Amoxicillin may interact with other medicines that you may be taking, including prescription or over-the-counter drugs, vitamins, and herbal supplements. Either amoxicillin or the other medicine can be affected and cause serious side effects. To help avoid harmful interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbal supplements you are taking. To find out how this drug might interact with something else you are taking, talk to your doctor or pharmacist.

This is not a complete list of drugs that may interact with amoxicillin. However, examples of drugs that may interact with amoxicillin include:

Birth control pills

Amoxicillin can reduce the effectiveness of birth control pills. This may increase the chance of pregnancy. If you are taking birth control pills, use an additional form of birth control, such as a condom, while taking this drug.

Blood thinner medicines

Bleeding may be more likely when amoxicillin is used with blood thinner medicines. Lowering the dose of the blood thinner may be necessary; check with your doctor. Examples of blood thinner medicines include:

  • Warfarin (Coumadin)

Allopurinol

When amoxicillin is administered with allopurinol (Zyloprim), a drug used to treat gout, it may increase the risk of rash.

Probenecid

Probenecid, a drug used commonly for gout, may increase the levels of amoxicillin in the body. Sometimes probenecid is used with antibiotics to help increase or extend their effects. Your doctor will monitor your therapy if you are prescribed probenecid with amoxicillin.

Other antibiotics

Certain antibiotics, such as those called tetracyclines, may interfere with the ability of amoxicillin to fight your infection. However, your doctor might prescribe other types of antibiotics with amoxicillin to help fight the infection. Tell your doctor about other antibiotics you may already be taking when they prescribe you amoxicillin, such as.

  • Doxycycline (Anticlate, Doryx, Doxy 100, Doxy 200, Oracea, Vibramycin)
  • Minocycline (Dynacin, Minocin, Minolira, Solodyn, Ximino)
  • Tetracycline (Achromycin V)

Laboratory Tests

Amoxicillin may cause a false-positive result when testing for urine glucose (sugar) using certain tests, such as Clinitest tablets, Benedict’s Solution, or Fehling’s Solution. It is recommended to use a certain test that amoxicillin does not interfere with, such as Clinistix or TesTape. Talk with your healthcare professional if you are taking amoxicillin during laboratory tests for urine glucose.

Disclaimer: Since drugs interact differently in each person, this information is not guaranteed to include all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbal supplements, and over-the-counter drugs that you are taking.

Other amoxicillin alerts

This drug comes with several alerts:

Diarrhea warning

Antibiotics can commonly cause diarrhea that ends when the antibiotics are stopped. Diarrhea that occurs later, as late as two months after stopping the antibiotic, may be a sign of an intestinal infection. Call your doctor if you have watery or bloody stools, stomach cramps, or fever.

Warnings for other groups

For children: Amoxicillin is used in infants, children and adolescents. Your doctor will prescribe different dosing in infants younger than 3 months old.

Kidney disease: Kidney disease may affect how the drug is removed from your body. If you have kidney disease, your healthcare provider may start with a lower dose and monitor for side effects.

For elderly patients: Being aged 65 years or older may increase your risk of side effects related to amoxicillin. If you are 65 years or older, your healthcare provider may start you at a lower dose and monitor your therapy.  

Call your doctor right away if you have serious side effects. Seek emergency care (call 911) if you experience life-threatening symptoms, such as difficulty breathing; chest pain; loss of consciousness; sudden vision changes; or swelling of the face, mouth, tongue or throat.

For pregnant and breastfeeding women

There are no known issues with taking amoxicillin for women who are pregnant or breastfeeding. If you are concerned about taking amoxicillin while pregnant or breastfeeding, talk with your doctor.

Can I take amoxicillin when pregnant?

Amoxicillin should be used with caution in pregnancy, but amoxicillin is generally considered safe during pregnancy if the treatment is necessary. Tell your doctor if you are pregnant before starting amoxicillin.

Can I take amoxicillin when breastfeeding?

Amoxicillin can pass into breast milk so may affect your baby. However, you may be able to continue breastfeeding while taking amoxicillin. Talk to your doctor about the best way to feed your baby if you are taking amoxicillin.

How and when to take amoxicillin

This drug is administered by mouth with or without food. Take the medication close to the same time(s) each day.

The liquid suspension is mixed by the pharmacy before you receive it. Keep the liquid suspension in the bottle it originally came in, tightly closed, refrigerated (if possible), and out of reach of children. Shake the suspension each time before use. You may administer the suspension directly in a child’s mouth or you may mix with other cold liquids, such as formula, milk, fruit juice, water, or ginger ale. Discard any unused liquid suspension after 14 days.

Thoroughly chew or crush the chewable tablets before swallowing. Do not crush or chew the capsules or regular tablets; swallow the capsules or tablets whole with a full glass of water.

Even if you start to feel better when taking amoxicillin for an infection, continue taking amoxicillin for the full number of days prescribed by your doctor. Skipping doses or not finishing the full treatment course can make amoxicillin less effective for your infection or lead to bacteria that are not treatable by antibiotics in the future.

All possible dosages and forms may not be included here. Your dose, form, and how often you take amoxicillin will depend on:

  • Condition being treated
  • How you react to the first dose
  • Other medical conditions you have
  • Severity of your condition
  • Your age
  • Your weight

Drug forms and strengths

  • Capsule
    • 250 mg, 500 mg

  • Chewable tablet
    • 125 mg, 250 mg

  • Liquid suspension
    • 125 mg/5 mL, 200 mg/5 mL, 250 mg/5mL, 400 mg/5 mL

  • Tablet
    • 500 mg, 875 mg

Dosage for infections of the ear, nose, throat, skin, or urinary tract

  • Adult dosage (age ≥ 18 years)
    • Typical dosage (mild or moderate): 250 to 500 mg every 8 to 12 hours
    • Typical dosage (severe): 500 to 875 mg every 8 to 12 hours
  • Children > 3 months        
    • Typical dosage (mild or moderate): 20 to 25 mg/kg/day. The total dose is divided and administered 2 to 3 times per day (every 8 to 12 hours).
    • Typical dosage (severe): 40 to 45 mg/kg/day. The total dose is divided and administered 2 to 3 times per day (every 8 to 12 hours).
  • Children ≤ 3 months
    • Typical dosage: Up to 30 mg/kg/day. The total dose is divided and administered two times per day (every 12 hours).

Dosage for infections of the lungs (lower respiratory tract)

  • Adult dosage (age ≥ 18 years)
    • Typical dosage (mild, moderate or severe): 500 to 875 mg every 8 to 12 hours
  • Children > 3 months
    • Typical dosage (mild, moderate or severe): 40 to 45 mg/kg/day. The total dose is divided and administered 2 to 3 times per day (every 8 to 12 hours).
  • Children ≤ 3 months
    • Typical dosage: Up to 30 mg/kg/day. The total dose is divided and administered two times per day (every 12 hours).

Dosage for H. pylori infection

  • Adult dosage (age ≥ 18 years)
    • Typical dosage (triple therapy): 1 gram amoxicillin (with clarithromycin and lansoprazole) every 12 hours
    • Typical dosage (dual therapy): 1 gram amoxicillin (with lansoprazole) every 8 hours

If you miss a dose of amoxicillin

Take your missed dose as soon as you remember unless it is almost time for your next dose. If it is almost time for your next dose, skip the missed dose and stay with your normal schedule. Do not take more than your prescribed dose.

If you take too much amoxicillin

If you take too much amoxicillin, you have a higher risk of having side effects caused by this drug. If you think you’ve taken too much of this drug, call your doctor or local poison control center at 1-800-222-1222.

Seek emergency care (call 911) if you experience life-threatening symptoms, such as difficulty breathing; chest pain; loss of consciousness; sudden vision changes; or swelling of the face, mouth, tongue or throat.

Helpful tips when taking amoxicillin

Keep these considerations in mind if your doctor prescribes amoxicillin for you.

General

  • Amoxicillin is an antibiotic used to treat bacterial infections. Even if you start to feel better when taking amoxicillin for an infection, continue taking amoxicillin for the full number of days prescribed by your doctor. Skipping doses or not finishing the full treatment course can make amoxicillin less effective for your infection or lead to bacteria that are not treatable by antibiotics in the future.
  • Amoxicillin is not used to treat viral infections, such as the common cold.

Storage

  • Store the liquid suspension in the refrigerator if possible (but it may be stored at room temperature if a refrigerator is not available). Discard unused suspension after 14 days.  
  • Store the tablets, chewable tablets, and capsules at room temperature between 68°F and 77°F (20°C to 25°C).
  • Do not store this medication in moist or damp areas, such as bathrooms.

Alcohol

There are no known interactions with amoxicillin and alcohol. If you are concerned about taking amoxicillin while drinking alcohol, talk with your doctor.

Refills

Your doctor will write the number of authorized refills on your prescription. Talk with your pharmacist if you have questions about refills.

Travel

When planning to travel, keep these tips in mind for packing your medication:

  • Bring enough medication for the full number of days of your trip, plus at least two days to be safe.
  • Keep your medication with you, in a purse or a carry-on bag if flying. Do not put it into a checked bag in case you are separated from your luggage.
  • Liquid medications are exempt from the 3-1-1 liquid rule for flying.
  • Keep your medications in their original containers, if possible, to reduce delays during airport or security screening. Keep all your medications together to expedite the process.
  • Avoid leaving your medication in a parked car for extended periods to protect it from extreme temperatures (hot or cold).

Availability

Many pharmacies stock this drug. When filling your prescription, you can call ahead to make sure your pharmacy carries it and has it in stock.

Prior Authorization

Many insurance companies do not require a prior authorization for this drug. Health plans may prefer certain drugs within this medication class over others. If a prior authorization is needed, your doctor will need to get approval from your insurance company before your insurance company will pay for your prescription.

Medications similar to amoxicillin

Amoxicillin is an antibiotic from the class of penicillin-like antibiotics. There are other medications that work like amoxicillin. These include:

  • Amoxicillin/clavulanate (Augmentin)
  • Amoxicillin/lansoprazole/clarithromycin (Prevpac)
  • Amoxicillin/omeprazole/rifabutin (Talicia)
  • Amoxicillin/omeprazole/clarithromycin (Omeclamox-Pak)
  • Ampicillin
  • Dicloxacillin
  • Penicillin V Potassium

Each medication has its own benefits and side effects profile. Your doctor will help determine the best option for you.

Discontinuing use of amoxicillin

Do not stop taking this drug unless instructed by your doctor.

Healthgrades Disclaimer:

This information is for educational purposes only. It should not be interpreted as medical advice, diagnosis or treatment. Healthgrades takes every effort to ensure this information is accurate and up to date. This content is not intended to cover all possible uses, side effects, warnings, precautions, allergic reactions, or drug interactions. Do not assume that the absence of such information means the medication is safe for your personal use. Always consult your doctor, pharmacist, or healthcare professional before taking or discontinuing any medication.

Medical Reviewer: University of Illinois Chicago Drug Information Group
Last Review Date: 2021 Sep 14
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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  2. Amoxicillin package insert. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=13bd4214-9b7f-425b-af5f-fc1ddc678230
  3. Amoxicillin chewable tablet package insert. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=00c35e29-0b05-4232-a4d6-38a230102ef5