ATC Code J01CA04
Formula C16H19N3O5S
Molar Mass (g·mol−1) 365,40
Physical State solid
Melting Point (°C) 194
PKS Value 3.2
CAS Number 26787-78-0
PUB Number 33613
Drugbank ID DB01060
Solubility moderate in water / poor in ethanol


Amoxicillin is a broad-spectrum antibiotic and belongs to the class of β-lactam antibiotics. Areas of application include infections of the gastrointestinal tract, urinary and respiratory tract, ear and skin. With a few exceptions, the spectrum of activity mainly includes gram-positive bacteria. Amoxicillin is only available with prescription so mono or combination preparation.

Amoxicillin is most commonly administered in tablet form or as a juice.



Amoxicillin acts by interfering with the synthesis of the cell wall of bacteria. It binds to certain proteins in their cell wall and prevents certain cross-links from being produced in it. The cell wall subsequently becomes unstable and collapses. Amoxicillin thus inhibits further multiplication of the pathogens and thus contributes to fighting the infection.


Amoxicillin has a bioavailability of about 60%. This means that 60% of the dose can reach the bloodstream and exert its effect. Plasma protein binding is 17% and the plasma half-life is approximately 61 minutes. Amoxicillin is broken down in the liver and excreted mainly by the kidneys.

Drug Interactions

When taken concomitantly with probenecid, dose adjustment may be because probenecid may accelerate excretion. There may be an increased likelihood of allergic reactions if taken with allopurinol. Concomitant use with tetracyclines may decrease the effectiveness of amoxicillin. Concomitant use with methotrexate may increase side effects.


Mild overdoses with amoxicillin are harmless due to the wide therapeutic range. Symptoms of severe overdose include abdominal pain, acute renal failure, hematuria, diarrhea and vomiting, skin rashes, and dizziness.

Side effects

The most common side effect is diarrhea. The occurrence of nausea with or without vomiting is also possible. Prolonged use or high doses of this antibiotic may affect the intestinal flora. This can lead to sometimes severe infections in the gastrointestinal tract. Infections of the vagina and skin are also more likely due to the disruption of the natural microbiome.

Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

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