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What are Penicillins

Penicillins are a type of antibiotic derived from Penicillium fungi. Alexander Fleming discovered the first penicillin in 1928 (benzylpenicillin also called penicillin G). Since then, several other penicillins have been derived, and the original structure has been modified to create new penicillins with enhanced effectiveness against a broader range of bacteria. Other penicillins include penicillin V (phenoxymethylpenicillin), amoxicillin, ampicillin, cloxacillin, flucloxacillin, piperacillin, and ticarcillin.

Penicillins are bactericidal (kill bacteria). Hypersensitivity reactions, such as rash, itch, nausea, or vomiting, can be common among penicillins, although true penicillin allergy resulting in anaphylaxis is rare (estimated frequency of 1 to 5 people per 10,000 cases of penicillin therapy). Individuals who develop anaphylaxis to penicillin should not be given any other type of penicillin. Some people who develop anaphylaxis with penicillin may also be hypersensitive to cephalosporin antibiotics; however, the incidence of cross-reactivity appears lower than previously thought and likely to only apply to certain cephalosporins.

Types of Penicillins

Please refer to the drug classes listed below for further information.