Amoxicillin: What Is It? What Does Amoxicillin Treat?

Amoxicillin is a widely-used antibiotic drug. It belongs to the penicillin group of drugs and is prescribed to treat certain infections that are caused by bacteria.


Following the expiration of its patent in 1998, amoxicillin has been produced by several pharmaceutical companies using different brand names. In the US it can be purchased as Amoxicot, Amoxil, DisperMox, Moxilin and Trimox.

Here are some key points about amoxicillin. More detail and supporting information is in the main article.

  • Amoxicillin works by preventing bacteria from growing, and killing them.
  • Amoxicillin can be used to treat infections caused by bacteria but not those caused by viruses.
  • Amoxicillin can also be used in combination with other medications to treat certain stomach ulcers.
  • Amoxicillin is dispensed in a wide variety of forms, ranging from tablets to liquid drops.
  • Common side effects of amoxicillin include diarrhea, candidiasis (yeast overgrowth) and tooth discoloration.
  • Amoxicillin can reduce the effectiveness of certain birth control measures.
  • Amoxicillin interacts with several other forms of medication, occasionally in a negative manner.
  • Amoxicillin has been known to cause false positive results in urine glucose tests.
  • Alcohol does not affect how amoxicillin works but patients are not advised to consume it while undergoing a course of treatment.

What is amoxicillin?

Amoxicillin belongs to a group of drugs called the penicillins which originate from a form of fungi called Penicillium fungi.

Penicillins are antibiotic drugs, meaning that they are used to treat infections caused by bacteria and to eliminate the bacteria themselves.

Amoxicillin fights bacteria by preventing them from forming cell walls and stopping them from growing. This kills the bacteria and eventually eradicates the infection.

Amoxicillin is not known to be effective against viral infections such as colds and flu.

Conditions such as these are best treated with antiviral medication or vaccination where available, depending on the illness.

What conditions does it treat?

As an antibiotic, amoxicillin is used to treat certain infections that have been caused by bacteria.

The following are conditions that amoxicillin can be prescribed to treat on its own:

  • Bronchitis
  • Ear infection
  • Gonorrhea
  • Lyme disease
  • Pneumonia
  • Skin infection
  • Throat infection
  • Tonsillitis
  • Typhoid
  • Urinary tract infection.

Amoxicillin can also be used in combination with another antibiotic called clarithromycin in order to treat stomach ulcers caused by H. pylori bacterial infection. These drugs can also be augmented with the use of lansoprazole to help reduce stomach acid and symptoms of acid reflux.

Health care providers sometimes prescribe amoxicillin for certain heart problems, to prevent chlamydia during pregnancy and as a prophylactic to prevent bacterial infection in newborns or of the heart valve after surgical procedures. Amoxicillin should only be used "off-label" if specifically recommended by a heath care provider.

Amoxicillin has also been recommended by the Centers for Disease Control and Prevention (CDC) and the Johns Hopkins Working Group on Civilian Biodefense as an "off-label" therapeutic option for patients that may have been exposed in inhalational anthrax. They recommend it as an option for patients who may not be able to have officially approved treatments.

How is amoxicillin taken?

Amoxicillin can be dispensed in several forms to be taken orally: as a dry tablet, chewable tablet, capsule, a suspension (liquid preparation) or drops for children.

Amoxicillin is normally taken either twice a day (every 12 hours) or three times a day (every 8 hours), depending on the doctor's instruction. It may be taken with or without food, and if being taken in liquid form it can be mixed with other liquids such as baby formula, fruit juice, milk and water.

Liquids and drops should be shaken thoroughly before use to ensure that the medication is distributed evenly. Tablets and capsules should be taken with water and chewable tablets should be fully chewed before they are swallowed.

It is important to follow the exact dosage and frequency as instructed by health care providers. If a dose is missed, one should be taken as soon as possible unless it is nearly time for the next dose. Never take a double dose to make up for a missed one.

Even if symptoms resolve, it is important that a treatment course is followed right to the end. Discontinuing treatment before the end of the prescribed course increases the risk of bacteria developing a resistance to the antibiotic; there is also a chance that the infection could return.


Source: James McIntosh