Gemifloxacin

Gemifloxacin is a prescription drug used for the treatment of various bacterial infections. It belongs to a family of antibiotics called quinolones. Other members of this family include ciprofloxacin (Cipro) and levofloxacin (Levaquin). The Food and Drug Administration approved the use of gemifloxacin in April 2003. Gemifloxacin is marketed as Factive by Oscient Pharmaceuticals.

Scanning Electron Micrograph of Streptococcus pneumoniae. These bacteria cause pneumonia. Gemifloxacin is affective against these bacteria and many others that cause cause community-aquired pneumonia. Source: CDC Public Health Image Library

Uses

Gemifloxacin is used for the treatment of infections caused by a variety of bacteria:

• Sudden onset of chronic bronchitis symptoms caused by infections with Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, or Moraxella catarrhalis
• Community-acquired pneumonia caused by Streptococcus pneumoniae (including multi-drug resistant strains), Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydia pneumoniae, or Klebsiella pneumoniae

How Gemifloxacin is Taken

Gemifloxacin is taken orally and is available in 320-mg tablets. The recommended dose is 320 mg daily.

How Gemifloxacin Works

Gemifloxacin, like other quinolones, acts by inhibiting bacterial DNA synthesis through the inhibition of two enzymes (DNA gyrase and topoisomerase IV) that are essential for bacterial reproduction. Gemifloxacin is a broad-spectrum antibiotic, which means it is effective against gram-negative and gram-positive bacteria.

Resistance to treatment with drugs like gemifloxacin results form mutations in the genes encoding one or both of these enzymes. But, because gemifloxacin inhibits two enzymes, this drug is effective against many infections that are not susceptible to treatment with other quinolones.

How the Body Affects Gemifloxacin

Peak circulating levels of temifloxacin occur approximately 0.5–2 hours post-dosing. Gemifloxacin is metabolized to a limited extent by the liver. Approximately 61% of the original dose is excreted in the feces and 36% in the urine.

Side Effects

The most common side effects of gemifloxacin in clinical trials, which occurred in 2% or more of patients, were the following:

• diarrhea
• rash
• nausea
• headache
• abdominal or gastrointestinal pain
• vomiting
• dizziness

Risks and Precautions

Hypersensitivity reactions, including severe allergic reactions, have occurred with gemifloxacin. The risk of these reactions can be reduced if gemifloxacin is not used in people who are allergic to other quinolone antibiotics.

Some quinolones cause phototoxicity, which is damage to the skin or eyes upon exposure to sunlight or bright indoor lights. This risk is minimal if people receiving quinolones like gemifloxacin avoid excessive sunlight or artificial ultraviolet light (such as tanning beds).

Gemifloxacin may increase the QT interval. The QT interval is a measure of heart function. It measures electrical conduction, and a slow interval may indicate slow conduction. Slow electrical conduction could lead to abnormal heart beats. The heart abnormalities often exclude people with pre-existing heart problems from using gemifloxacin.

Drug Interactions

The risk of QT prolongation is increased if femifloxacin is taken with other drugs that impair heart function:

• some types of antiarrhythmic drugs *e.g., procainamide, quinidine, and amiodarone (Cordarone)
• cisapride (Propulsid)
• erythromycin
• some antipsychotics
• some tricyclic antidepressants

Antacids that contain magnesium and aluminum reduce concentrations of gemifloxacin in the blood. However, they have little effect when taken three hours before or two hours after gemifloxacin. Similarly, sucralfate reduces absorption of gemifloxacin and it should be taken at least two hours after the antibiotic.

Research

The effectiveness of gemifloxacin and clarithromycin were compared in a clinical trial of 712 patients experiencing a worsening of bronchitis symptoms.^[1] Gemifloxacin and clarithromycin had similar success rates, 85%, at he 2–3 week follow up. However, 71% of gemifloxacin-treated and 59% of clarithromycin-treated patients were free of symptoms over the whole study period (26 weeks).

The effectiveness of gemifloxacin and ceftriaxone/cefuroxime was compared in 341 hospitalized patients with community-acquired pneumonia.^[2] Success rates in both treatment groups were over 90%.

References

1. ↑ Wilson R, Schentag JJ, Ball P, Mandell L; 068 Study Group. A comparison of gemifloxacin and clarithromycin in acute exacerbations of chronic bronchitis and long-term clinical outcomes. Clin Ther. 2002 Apr;24(4):639-52. Abstract
2. ↑ Lode H, File TM Jr, Mandell L, et al. Oral gemifloxacin versus sequential therapy with intravenous ceftriaxone/oral cefuroxime with or without a macrolide in the treatment of patients hospitalized with community-acquired pneumonia: a randomized, open-label, multicenter study of clinical efficacy and tolerability. Clin Ther. 2002 Nov;24(11):1915-36. Abstract

External Links

FDA: Patient Information Sheet