Drug Groups

approved; withdrawn

Description

Grepafloxacin hydrochloride (Raxar®, Glaxo Wellcome) is an oral broad-spectrum quinoline antibacterial agent used to treat bacterial infections. Grepafloxacin was withdrawn in the United States due to its side effect of lengthening the QT interval on the electrocardiogram, leading to cardiac events and sudden death. [Wikipedia]

Indication

For treatment of adults with mild to moderate infections caused by susceptible strains of Haemophilus influenzae, Streptococcus pneumoniae, or Moraxella catarrhalis.

Pharmacology

Grepafloxacin has in vitro activity against a wide range of gram-positive and gram-negative aerobic microorganisms, as well as some atypical microorganisms.

Toxicity

Withdrawn from the US market in 1999 due to associations with QTc prolongation and adverse cardiovascular events.

Affected Organisms

Biotransformation

Primarily hepatic via CYP1A2 and CYP3A4. The major metabolite is a glucuronide conjugate; minor metabolites include sulfate conjugates and oxidative metabolites. The oxidative metabolites are formed mainly by the cytochrome P450 enzyme CYP1A2, while the cytochrome P450 enzyme CYP3A4 plays a minor role. The nonconjugated metabolites have little antimicrobial activity compared with the parent drug, and the conjugated metabolites have no antimicrobial activity

Absorption

Rapidly and extensively absorbed following oral administration. The absolute bioavailability is approximately 70%.

Half Life

15 ± 3 hours

Protein Binding

50%

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