iCliniq logo

Ask a Doctor Online Now

HomeHealth articlesamoxicillinAmoxicillin - How to Use | Dosage | Side Effects |

Amoxicillin - How to Use, Dosage, and Side Effects

Verified dataVerified data
Amoxicillin - How to Use, Dosage, and Side Effects

5 min read


Amoxicillin is a penicillin-type antibiotic used to treat a wide range of bacterial infections. It is a broad-spectrum semisynthetic antibiotic similar to Ampicillin, except the resistance to gastric acids.

Medically reviewed by

Dr. C. Elanchezhian

Published At May 17, 2019
Reviewed AtNovember 23, 2022


Amoxicillin is a penicillin-type antibiotic that works by killing and preventing the growth of bacteria. It only works on infections caused by bacteria and not viral infections like cold and flu. It is also used with other medications like Clarithromycin and Lansoprazole to treat H.pylori infection. Amoxicillin is commonly prescribed with Clavulanic acid (a beta-lactamase inhibitor), as it is susceptible to beta-lactamase degradation.

Always use Amoxicillin or any other antibiotic only when your doctor prescribes it. Indiscriminate use and using it when you do not have a bacterial infection decreases the effectiveness of the medicine when you actually need it.

Drug Group:

Amoxicillin is a beta-lactam antibiotic that belongs to extended-spectrum penicillin (aminopenicillin) used to treat a wide range of bacterial infections. It is a broad-spectrum antibiotic (semisynthetic) similar to Ampicillin, except for the resistance to gastric acids. All the drugs under beta-lactam antibiotics contain a beta-lactam ring in their structure which is essential for their antimicrobial property. The other drugs that belong to this group of penicillin-type antibiotics are,

  1. Natural Penicillin - Benzylpenicillin or Sodium Penicillin G.

  2. Semisynthetic Penicillins -

  1. Acid Resistant Alternative to Penicillin G - Penicillin V.

  2. Extended Spectrum Penicillin

  • a)Aminopenicillins:

- Ampicillin.

- Amoxicillin.

- Bacampicillin.

  • b)Antipseudomonal Penicillin:

- Carbenicillin.

- Piperacillin.

- Mezlocillin.

What Is Amoxicillin Used For?

This medicine is used to treat the following bacterial infections:

  • Bronchitis.

  • Pneumonia.

  • Ear infection.

  • Tonsillitis.

  • Typhoid.

  • Urinary tract infections.

  • Gonorrhea.

  • Strep throat.

  • Skin infections.

  • Lyme disease.

  • Helicobacter pylori infection.

  • To prevent bacterial endocarditis.

  • To prevent chlamydia during pregnancy.

How Does Amoxicillin Work?

It belongs to the class of beta-lactam antibiotics, where beta-lactams act by binding to penicillin-binding proteins. It is,

  • Bactericidal.

  • Inhibits bacterial cell wall synthesis.

  • Inhibits cleavage of terminal d-alanine and transpeptidation.

  • Inhibits bacterial cell wall cross-linking.

  • Bacteria that produce deficient cell walls undergo lysis.

It starts to work by inhibiting the d-alanine and transpeptidation process, which means cross-linking the cell wall synthesis, which leads to activation of enzymes (autolytic) in the bacterial cell wall. So, it stops bacterial growth, treating only bacterial infections, and does not work for viral infections such as common cold, flu, etc. When an antibiotic is used in unwanted situations, it can cause resistance and may not function for future infections.

Onset Of Action:

The time required (onset) for Amoxicillin to start acting is 30 minutes, and its half-life varies according to age groups, that is, 3.7 hours in newborns and 1.4 hours in adults. Generally, an orally administered dose of 250 to 500 mg reaches its peak within 1 to 2 hours after taking the drug.

How to Use Amoxicillin?

Take antibiotics or any other medicine only if your healthcare provider prescribes them. Avoid buying over-the-counter medicines and self-medicating. Take the tablet for as many days as prescribed by your doctor, even if your symptoms have reduced. Stopping the antibiotic without finishing the course might increase the risk of the bacteria developing a resistance to the antibiotic, and the infection could recur.

Amoxicillin is available as:

  • A dry tablet or capsule - Tablets and capsules should be taken with water.

  • A chewable tablet - Chewable tablets should be properly and completely chewed before swallowing.

  • A suspension - Oral suspensions have to be mixed with water before consuming them.

  • Syrup - The syrup bottle should be shaken properly before taking. Shaking distributes the medicine evenly throughout the liquid.

What Is the Dosage of Amoxicillin?

The strength and duration of this medicine will be different for different patients, as it depends on the severity of the infection. The average doses used for a bacterial infection are:

  • Adult - 250 to 500 mg every 8 hours or 500 to 875 mg every 12 hours.

  • Children - 20 to 40 mg/kg per day.

  • Infants 3 months or younger - 30 mg/kg per day.

Dosage for Adults:

Dosage for Adults

Dosage for Children:

Dosage for Children

What Are the Drug Warnings and Precautions?

  1. Finish the entire treatment as prescribed by your doctor.

  2. You should not stop taking this drug if you start to feel better. However, it is always important to take the medication until the doctor has mentioned taking it as the infection can last longer.

  3. Sometimes you start developing a resistance to the medication; that is, if you come to get a bacterial infection in the future, amoxicillin will not help with it.

  4. Amoxicillin may sometimes cause diarrhea, so seek the doctor when on bloody or watery diarrhea, which can or cannot be associated with stomach cramps and fever.

  5. This drug can cause severe allergic reactions and can cause death. So, inform your doctor if you have ever had an allergy to this drug or the ingredients present in this drug.

  6. Also, tell your doctor that your risk for an allergic reaction may be higher if you are allergic to other antibiotics, such as,

  • Penicillins.

  • Cephalosporins.

7. On taking this drug, when you experience trouble breathing or swelling of the throat or tongue, stop the medication and immediately get a medical emergency.

Missed Dose:

Depending on the severity of infection, Amoxicillin is generally taken twice or thrice a day, that is, every 12 or 8 hours. If you somehow miss a tablet, then take it as soon as you remember. But if it is almost time for the next dose, then skip the missed tablet and never take a double dose.

What Are the Side Effects of Amoxicillin?

Side effects of Amoxicillin

Some of the common side effects of Amoxicillin are:

  • Severe allergic reaction to penicillin (Anaphylactic shock).

  • Skin rashes or hives.

  • Seizures.

  • Dark-colored or bloody urine.

  • Yellowish discoloration of eyes and skin.

  • Easy bruising.

  • Unusual bleeding.

  • Difficulty in breathing.

  • Tiredness.

  • Diarrhea.

  • Swelling around the eyes.

  • Swelling of the face and throat.

  • Clay-colored stools.

  • Stomach cramps.

  • Fungal infections like candidiasis.

  • Nausea.

  • Vomiting.

  • Weezing.

  • Change in taste.

  • Swelling of the lips and tongue.

  • Headache.

  • Blisters.

  • Difficulty in swallowing.

  • Peeling of the skin.

If you notice any of these symptoms, stop using the medicine, call your doctor and get medical help right away. All these are not a complete list of side effects, and this drug causes some other side effects.

What Are the Signs and Symptoms of an Allergic Reaction?

The signs and symptoms of an allergic reaction to Amoxicillin are:

And the signs of anaphylaxis are:

  • Difficulty breathing.

  • Nausea or abdominal cramps.

  • Dizziness.

  • Weak and rapid pulse.

  • Seizures.

  • Loss of consciousness.

  • Low blood pressure.

As soon as you notice signs of an allergic reaction, do not take more Amoxicillin and consult your physician immediately. A severe allergic reaction can also be fatal.

What Are the Drug Interactions ofAmoxicillin?

When a doctor prescribes Amoxicillin, always inform him or her about all the medicines that you are currently taking for any other illness. This will help the doctor analyze if it is safe to prescribe this antibiotic and will prevent unwanted drug interactions.

Amoxicillin might increase or reduce the effectiveness of other drugs that you might be taking or increase the risk of side effects by reducing the excretion of the drug. Some of the drug interactions to look out for are:

  • Anticoagulant drugs (Warfarin, Heparin).

  • Antibiotics (Tetracycline, Sulfonamides, Chloramphenicol).

  • Chemotherapy (Methotrexate).

  • Muscle relaxants (Carisoprodol, Cyclobenzaprine).

  • Cholera vaccine.

  • Birth control pills.

  • Gout treatment (Allopurinol).

Amoxicillin use could lead to false-positive results in urine glucose tests.

What Are the Common Brand or Trade Names of Amoxicillin?

The common brand or trade names of Amoxicillin are,

  • Trimox.

  • Amoxil.

  • Amoxil Pediatric Drops.

  • Trimox Pediatric Drops.

  • Dispermox.

  • Larotid Suspension.

  • Wymox.

  • Moxatag.

  • Polymox Suspension.

Does Amoxicillin Reduce the Effectiveness of Birth Control Measures?

Yes, Amoxicillin reduces the effectiveness of all birth control methods like birth control pills, vaginal rings, patches, etc. So, during the course of the antibiotic treatment, use barrier birth control methods like condoms.

For more information on the uses and side effects of Amoxicillin, consult a doctor online through phone or real-time video consultation.

Frequently Asked Questions


What does Amoxicillin treat?

Amoxicillin is an antibiotic that is used to treat bacterial infections of the ear, nose, throat, skin, genitourinary tract, respiratory tract, and gastrointestinal tract. Some of the common infections that can be treated are ear infectiosn, bronchitis, gonorrhea, Lyme disease, tonsillitis, and pneumonia


How long does Amoxicillin stay in your system?

The half-life, that is the duration of action of a drug, of Amoxicillin is 61.3 minutes. Around 60 % of medicine taken orally is excreted in the urine within 6 to 8 hours. It can be detected in the blood for up to 8 hours


What do Amoxicillin and Clavulanate treat?

The combination of Amoxicillin and Clavulanate is used to treat various bacterial infections. Clavulanate is a beta-lactamase inhibitor, which works by preventing bacteria from destroying Amoxicillin. And Amoxicillin stops the growth of bacteria


How long does it take for Amoxicillin to work?

You might feel better in a couple of days after starting Amoxicillin. Do not stop taking the medicine before the prescribed number of days. It is usually prescribed for 7 to 14 days


How long can Amoxicillin be taken?

Always take any medicine only if prescribed by a healthcare professional. Depending on the severity of the infection, Amoxicillin is prescribed for 7 to 14 days. If your doctor feels that you need to take it longer, he or she will prescribe it. Never self-medicate


How fast does Amoxicillin work for tooth infection?

For tooth infection, Amoxicillin is usually given thrice or twice daily for 5 to 7 days. Your dentist will know if you need antibiotics for your tooth infection


What are the allergic reactions to Amoxicillin?

Generally, Amoxicillin causes a mild skin rash, which is not serious. But if you experience other allergic reactions like itching, swelling of face or tongue, difficulty breathing or swallowing, and dizziness, get immediate medical help


Can you take Amoxicillin with other medicines?

Amoxicillin is usually prescribed with other antibiotics, painkillers, clavulanic acid, etc. But some of the medicines that should not be taken with Amoxicillin are Methotrexate, Warfarin, Heparin, Tetracycline, Sulfonamides, birth control pills, Allopurinol, Chloramphenicol, and Azithromycin


How fast does Amoxicillin work for UTI?

For UTI (urinary tract infection), Amoxicillin is generally prescribed for 1 to 3 days. Depending on the severity of your symptoms and medical history, a longer course might be needed


Is Amoxicillin a strong antibiotic?

Yes, Amoxicillin is a strong antibiotic as it treats a wide range of bacterial infection.


Can Amoxicillin be used for bronchitis?

Amoxicillin is primarily used to treat respiratory tract infection like pneumonia. For bronchitis, it is used only for allergic patients or patients who are intolerant to macrolides
Dr. C. Elanchezhian
Dr. C. Elanchezhian

General Medicine


Community Banner Mobile
By subscribing, I agree to iCliniq's Terms & Privacy Policy.

Source Article ArrowMost popular articles

Ask your health query to a doctor online

General Medicine

*guaranteed answer within 4 hours

Disclaimer: No content published on this website is intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek advice from your physician or other qualified healthcare providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website. Read our Editorial Process to know how we create content for health articles and queries.

This website uses cookies to ensure you get the best experience on our website. iCliniq privacy policy