Description

Gemifloxacin is a synthetic, broad-spectrum antibiotic that belongs to the fourth-generation fluoroquinolone class of drugs. It is available as an oral tablet and is considered a potent bactericidal agent, which means it kills bacteria directly.

Indications

Gemifloxacin is primarily indicated for the treatment of specific respiratory tract infections in adults (18 years of age or older) caused by susceptible bacteria. These indications are often limited to cases where other treatment options are not suitable. The main indications include:

• Acute bacterial exacerbation of chronic bronchitis (ABECB): Caused by bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.

• Community-acquired pneumonia (CAP): Used for mild to moderate cases caused by a range of bacteria, including Streptococcus pneumoniae (including multi-drug resistant strains), Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Klebsiella pneumoniae.

It’s important to note that due to concerns about serious side effects, regulatory agencies often recommend reserving fluoroquinolones like gemifloxacin for infections where other, safer antibiotics are not effective or cannot be used.

Mechanism of Action

Gemifloxacin’s bactericidal action is achieved by interfering with the essential processes of bacterial DNA replication, transcription, and repair. It accomplishes this by specifically inhibiting two key bacterial enzymes:

1. DNA Gyrase (Topoisomerase II): This enzyme is critical for maintaining the proper supercoiling of bacterial DNA. DNA gyrase unwinds and re-coils the DNA, a process necessary for replication and transcription. Gemifloxacin binds to this enzyme, preventing it from functioning and leading to double-strand breaks in the bacterial DNA.

2. Topoisomerase IV: This enzyme is essential for separating the replicated chromosomes into two distinct daughter cells during bacterial cell division. By inhibiting topoisomerase IV, gemifloxacin prevents the completion of cell division, leading to cell death.

Gemifloxacin is a fourth-generation fluoroquinolone, and a key feature of its mechanism is its “dual-targeting” ability. It has a high affinity for both DNA gyrase and topoisomerase IV. This dual action is particularly effective against bacteria that may have developed resistance to earlier-generation fluoroquinolones through mutations in one of these enzymes. By targeting both enzymes, gemifloxacin makes it more difficult for the bacteria to acquire high-level resistance.