Augmentin - How does it work?

Augmentin is a combination of amoxicillin and clavulanate.

Amoxicillin is a beta lactam antibiotics which binds to and inhibits penicillin binding protein (PBP). PBP is what makes the cell wall of the bacteria and, by inhibiting it, amoxicillin prevents new synthesis and replicating capacity of the bacteria.

The above image is a picture of the beta-lactam ring that binds to PBP.

However, bacteria are smart and they evolve at a rapid pace to overcome the antibiotics. One of the way that bacteria do this is to produce what's called the beta-lactamase which breaks the beta-lactam ring. The arrow on the picture shows where the beta-lactamse acts on to break the 4 carbon ring structure.

In order to deal with beta-lactamase, we added clavulanate to the mixture. Clavulanate is a beta-lactamase inhibitor. Thus it stops the activity of the enzyme to break down the antibiotics and let amoxicillin does what it is supposed to do.

Some of the side effect of this drug is nausea and vomiting that generally is better if taken with milk or food. Other side effects that are particularly higher with augmentin is diarrhea which is said to be up to 30% higher incidence than other antibiotics. Recently the FDA approved a higher dosage of amoxicillin combine with the same dose of clavulanate which seems to have less incidence of diarrhea than the older formulation.

Other more uncommon but dreaded complications are C. Diff colitis and steven-johnson syndrome. C. Diff pseudomembranous colitis can be treated with oral vancomycin or metronidazole (flagyl). If the disease evolved into toxic megacolon then surgical solution is required. In the case of steven-johnson syndrome, it's an autoimmune mediated response triggered by the penicillin-like medications. This syndrome is where the patient's skin sloughs off in patches leading to severe-burn like symptoms. Most of these patients are sent to the burn unit to be treated with mortality ranging from 3 to 90% depending on the severity of the disease. Treatment for steven-johnson is mostly supportive and discontinuing the offending agent (in this case the antibiotics.)