Amoxicillin - Use | Overdose | Side Effects

This article was medically reviewed by M.Pharm, Marko Tanaskovic on Thu, 27 Dec 2018. To read more about an author, click here.

Amoxicillin is a drug from the group of penicillin antibiotics. Amoxicillin works by killing bacteria and therefore is used to treat infections.

Amoxicillin is used in treatment of the following infections:

  • Respiratory tract infections (tonsillitis, pharyngitis, sinusitis, bacterial bronchitis, pneumonia)
  • Urinary tract infections
  • Skin and soft tissue infections
  • Infections caused by bacteria called Helicobacter pylori accompanies with stomach ulcers
  • Gonorrhea
  • Ear infections such as otitis media (middle ear inflammatory disease)

Amoxicillin is effective against a wide range of bacteria and therefore is one of the most commonly used antibiotics.


Amoxicillin should be avoided in the following conditions:

  • If you are allergic to amoxicillin and other antibiotics such as:
    • ampicillin,
    • co-amoxiclav,
    • cephalexin,
    • ceftriaxone,
    • cefepime,
    • cefaclor,
    • cefdinir and others. Symptoms of an allergy include:
      • itching of the skin,
      • redness of the skin,
      • skin rash,
      • swelling of the face,
      • swelling of the tongue,
      • swelling of the neck,
      • trouble breathing. Allergy can cause anaphylactic shock, and it is necessary to immediately contact your doctor if you notice any symptoms of an allergy.
  • If you have kidney disorders.
  • If you have viral infections (e.g. infectious mononucleosis also known as mono).
  • If you have liver disorders.

Do not use Amoxicillin in combination with alcoholic beverages.

Amoxicillin, like all other antibiotics can cause diarrhea. Consult your doctor about the medicine you need to take to treat diarrhea.

Amoxicillin may reduce the effect of the contraceptive pill and cause an unwanted pregnancy. Use extra protection while using Amoxicillin.

Use of Amoxicillin during pregnancy and breast feeding

According to FDA, Amoxicillin belongs to a group B (FDA: Group B). This means that animal studies have shown that Amoxicillin is not harmful to the fetus, but there are no studies on humans. Amoxicillin should be used during pregnancy only if the benefit to the mother outweighs the risk to the child.

Amoxicillin passes into breast milk and may harm your baby. Avoid breastfeeding while using Amoxicillin.

How to use Amoxicillin


Amoxicillin is usually taken at a dose of 500 mg three times a day. To treat mild infection Amoxicillin can be taken in a dosage of 250 mg three times a day or 500 mg twice a day.

To treat severe infections dose may be increased up to 1,500 mg (3 capsules of 500 mg) twice a day.

To treat urinary tract infections Amoxicillin is used at a dose of 3000 mg (6 capsules of 500 mg) only twice. The time period between doses should be at least 12 hours.

To treat gonorrhea Amoxicillin is used at dose of 3000 mg (6 capsules of 500 mg), and should be taken only once.


Dose should be adjusted according to body weight and it is usually 20-50 mg per kilogram of body weight. If your child's body weight is 30 kg, then the dose will be:

20 mg x 30 kg = 600 mg per day.

The dose may be increased depending on the severity of the infection. If your child cannot swallow the capsules, it is recommended to take Amoxicillin in the form of syrup.

Amoxicillin should be taken as long as your doctor tells you to, to cure the infection completely. Do not stop using Amoxicillin early even if you feel better! Follow the doctor's advice on how long you need to take Amoxicillin. If you stop using Amoxicillin early (e.g. a doctor has recommend you to take Amoxicillin for 7 days, and you stop after 5th day), you will not kill all the bacteria. Those bacteria that survive will develop a mechanism to fight against Amoxicillin and therefore Amoxicillin will not help you next time when you get an infection! Therefore, it is necessary to follow the doctor's instructions!

Amoxicillin can be taken with or without food.


If you take more Amoxicillin than your doctor recommended, contact your doctor. Symptoms of an overdose include: nausea, diarrhea, vomiting.

Tell your doctor if you are experiencing any of these symptoms.

Use with other medicines (Interactions)

Amoxicillin should be avoided with the following medications:

  • Birth control pills (e.g. Yasmin). Amoxicillin reduces the effect of contraceptive pills and the protection against unwanted pregnancy. Use some other protection while using Amoxicillin.
  • If you are taking oral anticoagulants used to treat thrombosis, such as: acenocoumarol (Sintrom, Sinkum 4), warfarin (Farin) and others.
  • If you are taking medicines to treat gout, such as: allopurinol, probenecid and others.

Tell your doctor about all medications and herbal medicines you are taking.

Side effects

Amoxicillin may cause the following side effects:

  • nausea,
  • vomiting,
  • diarrhea (blood in stool may occur),
  • allergy (skin rash, itching, swelling of the face, swelling of the tongue, difficulty breathing),
  • flu-like symptoms (fever, sore throat),
  • liver damage (loss of appetite, dark color of urine, jaundice-yellowing of the skin and eyes),
  • headache,
  • change in tongue color,
  • anemia and others.

Tell your doctor if you are experiencing any side effects.

Information on this website are provided for educational purposes only and are not intended for medical advice, diagnosis or treatment.

If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.