Floxacillin (Adverse effects)

Floxacillin is an antibiotic of the penicillin family used in the treatment of Gram-positive bacterial infections. Liver toxicity is one of the most serious adverse effects associated with the drug and certain genetic polymorphisms can increase the risk of presenting it.

Floxacillin or flucloxacillin is an antibiotic widely used in Europe and Australia for treating staphylococcal infections. It is a narrow-spectrum beta-lactam antibiotic of the penicillin class. It is used to treat infections caused by susceptible Gram-positive bacteria. Flucloxacillin is very similar to dicloxacillin; they are considered interchangeable.

Approximately 1 of every 10,000 persons who take this drug experience hepatic toxicity which in additional may be potentially fatal. Given that there are medicines that are not associated with these adverse side effects, floxacillin is not commercially available in the United States, nor in Spain.


  • Floxil®
  • Floxapen®
  • Flucinal®

Genes analyzed



Ali SE, Waddington JC, Lister A, et al.Identification of flucloxacillin-modified hepatocellular proteins: implications in flucloxacillin-induced liver injury. Toxicol Sci. 2023 Mar 20;192(1):106-116.

Daly AK, Donaldson PT, Bhatnagar P, et al.HLA-B*5701 genotype is a major determinant of drug-induced liver injury due to flucloxacillin. Nat Genet. 2009 Jul;41(7):816-9.

Lindh M, Hallberg P, Yue QY, Wadelius M.Clinical factors predicting drug-induced liver injury due to flucloxacillin. Drug Healthc Patient Saf. 2018 Nov 21;10:95-101.

Haven't you taken a DNA test yet?

Get your genetic test and find out all about yourself.

Starter DNA test

Ancestry, Traits and Wellness

Advanced DNA test

Health, Ancestry, Traits and Wellness

The DNA test you were looking for