Pronunciation: am-OX-i-sil-in
Generic name: amoxicillin
Brand names: Amoxil, Trimox, Moxatag
Dosage forms: oral capsule (250 mg; 500 mg), oral powder for reconstitution (125 mg/5 mL; 200 mg/5 mL; 250 mg/5 mL; 400 mg/5 mL), ... show all 4 dosage forms oral tablet (500 mg; 875 mg), oral tablet, chewable (125 mg; 250 mg)
Drug class: Aminopenicillins

Medically reviewed by Melisa Puckey, BPharm. Last updated on Aug 16, 2024.

What is amoxicillin?

Amoxicillin is a penicillin antibiotic used to treat bacterial infections such as tonsillitis, bronchitis, sinusitis, pneumonia, and infections of the ear, nose, throat, skin, or urinary tract.  

Amoxicillin clavulanate is a combination of amoxicillin and clavulanate potassium. The amoxicillin fights bacteria, and the clavulanate potassium helps prevent certain bacteria from becoming resistant to amoxicillin. 

Amoxicillin is also sometimes used together with another antibiotic called clarithromycin (Biaxin) to treat stomach ulcers caused by Helicobacter pylori infection. This combination is sometimes used with a stomach acid reducer called lansoprazole (Prevacid).

Amoxicillin 500mg and 250mg are available as tablets or capsules and as an oral suspension. Many brands and forms of amoxicillin are available, and not all brands are listed on this leaflet.

Amoxicillin side effects

Common amoxicillin side effects 

Common amoxicillin side effects may include nausea, vomiting, diarrhea, or rash. These side effects affected more than 1% of patients in clinical trials.

Serious amoxicillin side effects

Get emergency medical help if you have signs of an allergic reaction to amoxicillin (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Call your doctor at once if you have:

• severe stomach pain; or
• diarrhea that is watery or bloody (even if it occurs months after your last dose).

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may also report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

Do not use this medication if you are allergic to amoxicillin or to any other penicillin antibiotic, such as ampicillin (Omnipen, Principen), dicloxacillin (Dycill, Dynapen), oxacillin (Bactocill), penicillin (Beepen-VK, Ledercillin VK, Pen-V, Pen-Vee K, Pfizerpen, V-Cillin K, Veetids), and others.

Before using amoxicillin, tell your doctor if you are allergic to cephalosporins such as Omnicef, Cefzil, Ceftin, Keflex, and others. Also, tell your doctor if you have asthma, liver or kidney disease, a bleeding or blood clotting disorder, mononucleosis (also called "mono"), or any type of allergy.

Amoxicillin can make birth control pills less effective. Ask your doctor about using a non-hormone method of birth control (such as a condom, diaphragm, or spermicide) to prevent pregnancy while taking this medicine. Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Amoxicillin will not treat a viral infection such as the common cold or flu. Do not share this medication with another person, even if they have the same symptoms you have.

Antibiotic medicines can cause diarrhea. This may happen while you are taking amoxicillin, or within a few months after you stop taking it. This may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking this medicine and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Before taking this medicine

You should not use amoxicillin if you are allergic to any penicillin antibiotic, such as ampicillin, dicloxacillin, oxacillin, penicillin, or ticarcillin.

To make sure this medicine is safe for you, tell your doctor if you have:

• kidney disease;
• mononucleosis (also called "mono");
• diarrhea caused by taking antibiotics; or
• food or drug allergies (especially to a cephalosporin antibiotic such as Omnicef, Cefzil, Ceftin, Keflex, and others).

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Amoxicillin can make birth control pills less effective. Ask your doctor about using a non-hormonal birth control (condom, diaphragm, cervical cap, or contraceptive sponge) to prevent pregnancy.

It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk.

How should I take amoxicillin?

Take amoxicillin exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Take amoxicillin at the same time each day.

Some forms of amoxicillin may be taken with or without food. Check your medicine label to see if you should take your mediicne with food or not.

Shake the oral suspension (liquid) before you measure a dose.

Measure liquid medicine with the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon). You may mix the liquid with water, milk, baby formula, fruit juice, or ginger ale. Drink all of the mixture right away. Do not save for later use.

You must chew the chewable tablet before you swallow it.

Swallow the regular tablet whole and do not crush, chew, or break it.

If you are taking amoxicillin with clarithromycin and/or lansoprazole to treat stomach ulcer, use all of your medications as directed. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice.

Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication. Amoxicillin will not treat a viral infection such as the flu or a common cold.

Do not share this medicine with another person, even if they have the same symptoms you have.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using this medicine.

Store tablets and capsules at room temperature, away from moisture, heat, and light.

Liquid amoxicillin may need to be stored in a refrigerator or at room temperature, depending on the brand. Check your label for storage instructions. If stored in the refrigerator, do not allow it to freeze. Throw away any liquid medicine that is not used within 14 days after it was mixed at the pharmacy.

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What to avoid

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.

What other drugs will affect amoxicillin?

Tell your doctor about all your other medicines, especially:

• any other antibiotics;
• allopurinol;
• probenecid; or
• a blood thinner - warfarin, Coumadin, Jantoven;
• birth control pills.

This list is not complete. Other drugs may interact with amoxicillin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here; to check for interactions, click on the link below.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use amoxicillin only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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