Penicillin is an antibiotic that disturbs the cell wall synthesis in bacteria. It was initially derived from the mold Penicillium rubrum. Since then, a number of naturally occurring penicillins have been derived e.g. penicillin G (benzylpenicillin) and penicillin V (phenoxymethylpenicillin).
Other antibiotics obtained from penicillins include amoxicillin, ampicillin, flucloxacillin. These are classed as semisynthetic penicillins.
Penicillins are bactericidal and mainly active against gram-positive bacteria.
The most important side effect of penicillins is hypersensitivity, such as rashes or anaphylaxis. Patients who are allergic to one penicillin will be allergic to all.
Please refer to the drug classes listed below for further information.