Amoxicillin belongs to the group of aminopenicillins and is used as a broad-spectrum antibiotic. Since 1981, the active substance has been approved and has since been available under various trade names. The drug works against both Gram-negative and Gram-positive bacteria.

What is amoxicillin?

Amoxicillin belongs to the group of aminopenicillins and is used as a broad-spectrum antibiotic.

Amoxicillin is a so-called β-lactam antibiotic from the drug class of penicillins. In its molecular structure, a lactam ring is present, which mediates the antibiotic activity of the drug.

The drug has a wide range of applications against a wide variety of bacterial species. Sometimes combined use of amoxicillin with clavulanic acid may increase its efficacy. Amoxicillin has a bacteriocidal effect, which means killing bacteria, in contrast to bacteriostatic antibiotics, which inhibit growth.

The drug class of penicillins destroy only bacteria, but not animal and plant cells. The reason is the completely different structure of the respective cell membranes. Thus, like all penicillins, amoxicillin is relatively harmless to the human body. Amoxicillin is also relatively acid resistant and therefore can be administered orally without any problems without losing its effect.

Pharmacological action

The effect of amoxicillin is based on the interaction of the lactam ring with the cell membrane of the bacteria. Both gram-positive and gram-negative bacteria contain in their cell membrane as a building material the so-called polysaccharide peptide murein.

The lactam ring of the antibiotic forms peptide bonds with the murein, thus destroying the membranes of the bacteria. The membrane destroying effect unfolds among other things in cell division. The bacteria die off. Some bacteria, such as the staphylococci, produce the enzyme β-lactamase, which inactivates amoxicillin by destroying the β-lactam ring. Therefore, the sole use of amoxicillin against staphylococci is ineffective.

However, by combining amoxicillin with clavulanic acid, its spectrum of activity can be extended to include this bacterial species. Clavulanic acid namely inhibits the enzyme β-lactamase in its action. When antibiotics are used, as with amoxicillin, resistance develops slowly.

These resistances are caused by the development of insensitivity of the binding proteins to penicillin, by the amplification of the bacterial cell membranes or by the increased production of the enzyme β-lactamase. At least with this third type of resistance, the combined administration of amoxycillin with clavulanic acid has yet found a way to combat the bacterium.

Medical application & use

Amoxicillin has, as already mentioned, a wide range of applications against various bacterial species. In contrast to classic penicillin, amoxicillin also works against gram-negative bacteria.

Unlike Gram-negative bacteria, Gram-positive bacteria have a much thicker layer of murein in the membrane. The determination of Gram staining is therefore often carried out to find the appropriate antibiotic for use. Due to the broadband effect of amoxicillin, however, this test is not necessary here. Thus, in addition to the classic penicillin use, amoxicillin can also be used against Escherichia coli, Listeria, enterococci and various Proteus species.

Thus, many infectious diseases of the upper respiratory tract, the ear (middle ear inflammation), the urinary tract and the gastrointestinal tract are treatable with amoxycillin. The combination of amoxicillin with clarythromycin (bacteriostatic antibiotic) can also treat Helicobacter pylori infections in the stomach.

This bacterium is responsible, among other things for gastritis and gastric ulcer. People suffering from heart disease are often given preventative amoxicillin before surgery. During treatment, amoxicillin is mainly administered orally independently of ingestion, with the body absorbing up to 80 percent of the drug. The majority of the drug is excreted by the kidneys.

Risks & Side Effects

Basically Amoxicillin is well tolerated. It damages the intestinal flora less than other antibiotics. The drug is broken down quickly.

However, with the use of amoxicillin, as with all medicines, in some cases side effects are to be expected. It can cause skin rashes, upset stomach, nausea, vomiting, bloating and diarrhea.

Itching, fever, mucosal inflammation, dry mouth and impaired sense of taste are also observed. In rare cases, edema, anemia, liver disorders or kidney inflammation occur. Particularly dramatically, a penicillin allergy can cause anaphylactic shock.

In this case, therapy with amoxycillin should be discontinued immediately. Continuous use may result in a superinfection with resistant bacterial strains or yeasts.