gatifloxacin

Action and Spectrum

Actions and spectrum: 

gatifloxacin is a broad-spectrum fluoroquinolone antibiotic that exhibits bactericidal activity against the gram-negative and gram-positive bacteria. It works by inhibiting bacterial DNA synthesis and repair, thereby preventing bacterial growth and replication. 

gatifloxacin is particularly effective against respiratory tract pathogens such as Moraxella catarrhalis, Streptococcus pneumoniae and Haemophilus influenzae.

It is also effective against other gram-positive bacteria such as Staphylococcus aureus and Streptococcus pyogenes, as well as gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. 

Drug Interaction

Adverse Reaction

Frequency defined 

1-10% 

Conjunctival hemorrhage (1-4%) 

Dry eye (1-4%) 

Eye irritation (1-4%) 

Eyelid swelling (1-4%) 

Decreased visual acuity (1-4%) 

Chemosis (1-4%) 

Eye discharge (1-4%) 

Eye pain (1-4%) 

Red eye (1-4%) 

Taste disturbance (1-4%) 

Papillary conjunctivitis (5-10%) 

Increased lacrimation (5-10%) 

Keratitis (5-10%) 

Conjunctival irritation (5-10%)  

Frequency not defined 

endothelial corneal cell Injury 

Growth of the resistant organisms after prolonged use 

Hypersensitivity  

Post marketing reports 

Hypersensitivity, allergic dermatitis, pruritus, eye allergy, nausea 

Anaphylactic reactions, facial edema or angioedema, blepharitis, eye pruritus, dyspnea, eye swelling 

Vision blurred 

Black Box Warning

Black Box Warning: 

gatifloxacin has a black box warning regarding the increased risk of tendinitis and tendon rupture, particularly in older adults and those taking corticosteroids. Other potential risks include peripheral neuropathy, central nervous system effects, and worsening of myasthenia gravis. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

gatifloxacin is contraindicated in individuals who have demonstrated hypersensitivity to gatifloxacin or any other fluoroquinolone antibiotic. It is contraindicated in patients with tendon disorders related to fluoroquinolone use, as well as in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, as it may result in hemolytic anemia. gatifloxacin should not be used in children or adolescents under the age of 18, except in certain circumstances where the benefits outweigh the risks.  

Caution: 

• Hypersensitivity: gatifloxacin should not be used by patients who are hypersensitive to the medication, any of its components, or other quinolone antibiotics. 
• Tendinitis and tendon rupture: Tendinitis and tendon rupture have been reported with the use of gatifloxacin and can occur within 48 hours of starting treatment or even several months after completing treatment. 
• Peripheral neuropathy: Peripheral neuropathy has been reported with the use of gatifloxacin. Patients who experience symptoms such as pain, burning, tingling, numbness, or weakness in the arms or legs should contact their healthcare provider immediately. 
• Photosensitivity: gatifloxacin can cause photosensitivity. Patients should avoid exposure to direct sunlight or sunlamps and should wear protective clothing and sunscreen when outdoors. 
• Hepatotoxicity: Hepatotoxicity, including liver failure and death, has been reported with the use of gatifloxacin. Patients should be advised to contact their healthcare provider immediately if they experience symptoms of liver injury such as jaundice, dark urine, light-colored stools, nausea, vomiting, or abdominal pain. 
• QT prolongation: gatifloxacin can cause QT prolongation, which can lead to an irregular heartbeat and sudden death. It should be used under caution in patients who have a history of QT prolongation or who are taking medications that can prolong the QT interval. 
• Myasthenia gravis: gatifloxacin can exacerbate symptoms of myasthenia gravis, a neuromuscular disorder characterized by muscle weakness and fatigue. 
• Renal impairment: gatifloxacin should be used with caution in patients with renal impairment, as the drug is primarily eliminated by the kidneys. 
• Blood sugar levels: gatifloxacin can cause hypoglycemia or hyperglycemia, particularly in patients with diabetes. Patients should monitor their blood sugar levels regularly while taking gatifloxacin.

Comorbidities: 

• Liver disease: gatifloxacin is primarily metabolized in the liver, and patients with liver disease may be at increased risk of adverse effects. 
• Kidney disease: Dose adjustment may be necessary for patients with kidney disease as gatifloxacin is primarily excreted through the kidneys. 
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency: gatifloxacin has been associated with hemolytic anemia with G6PD deficiency. 
• Myasthenia gravis: gatifloxacin has been reported to cause exacerbation of myasthenia gravis, a neuromuscular disorder. 
• QT prolongation: gatifloxacin has been associated with QT prolongation, a condition that increases the risk of life-threatening arrhythmias. 

Pregnancy / Lactation

Pregnancy consideration: US FDA pregnancy category: C 

Lactation: It is not known whether gatifloxacin can pass into breast milk  

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: There is no evidence of risk to the fetus found in animal reproduction studies and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for an effect in humans, care must be taken for potential risks in pregnant women. 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite potential risks may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits These category drugs should be prohibited for pregnant women. 
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

gatifloxacin is a fourth-generation fluoroquinolone antibiotic that exhibits bactericidal activity against both the gram-positive and gram-negative bacteria. It acts by inhibiting the bacterial DNA gyrase and topoisomerase IV enzymes, which are essential for bacterial DNA replication, repair, and transcription. gatifloxacin is highly lipophilic, allowing it to penetrate bacterial cells effectively. 

After oral administration, gatifloxacin is rapidly and completely absorbed from the gastrointestinal tract. Its absolute bioavailability is approximately 96%. gatifloxacin is extensively distributed into the body tissues, including the respiratory tract, urinary tract, prostate gland, bile, and bone. It is primarily eliminated via renal and biliary excretion. gatifloxacin has a half-life of 7-14 hours and is eliminated from the body within 3-4 days.  

Pharmacodynamics: 

gatifloxacin is a broad-spectrum antibiotic that works by inhibiting bacterial DNA synthesis, which leads to bacterial cell death.

It belongs to the fluoroquinolone class of antibiotics and is active against the gram-negative and gram-positive bacteria, including those that are resistant to other antibiotics such as penicillin and cephalosporins.

gatifloxacin acts by inhibiting bacterial DNA gyrase and topoisomerase IV enzymes, which are essential for DNA replication and transcription. This results in the formation of defective DNA, leading to cell death. 

gatifloxacin also exhibits concentration-dependent bactericidal activity, which means that higher concentrations of the drug are more effective at killing bacteria.  

Pharmacokinetics: 

Absorption 

gatifloxacin is well absorbed from the gastrointestinal tract after oral administration, with peak plasma concentrations achieved within 1-2 hours. The absolute bioavailability of the oral tablet is approximately 96%. 

Distribution 

gatifloxacin is widely distributed in the body, with a volume of distribution of approximately 1.4 L/kg. It is highly protein-bound (approximately 20%) and can penetrate most body tissues and fluids, including the aqueous humor of the eye. 

Metabolism 

gatifloxacin is metabolized in the liver by several cytochrome P450 enzymes, including CYP1A2, CYP2C9, and CYP3A4. The major metabolite is a glucuronide conjugate. 

Elimination and excretion 

gatifloxacin and its metabolites are excreted primarily in the urine, with 20-30% of the dose excreted unchanged. The elimination half-life is 7-14 hours, depending on the dose and route of administration. gatifloxacin is also excreted in the feces to a lesser extent. 

Adminstartion

Administration: 

gatifloxacin is administered as an ophthalmic solution or ointment for the treatment of bacterial infections of the eye. The usual recommended dose is one or two drops of the solution applied to the affected eye(s) every 2-4 hours, or as directed by a healthcare professional. The ointment is applied to the inside of the lower eyelid every 8-12 hours, or as directed by a healthcare professional.

It is important to follow the dosing instructions provided by the healthcare professional, and to complete the full course of treatment to ensure the infection is fully treated. Before administering the solution or ointment, hands should be washed thoroughly, and the tip of the applicator should not touch any surface, including the eye, to avoid contamination. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: gatifloxacin 

Pronounced: (GAT-i-FLOX-a-sin)  

Why do we use gatifloxacin ? 

• Treatment of respiratory tract infections: gatifloxacin is used to treat respiratory tract infections such as acute exacerbation of chronic bronchitis and community-acquired pneumonia. 
• Treatment of urinary tract infections: gatifloxacin is also used to treat UTIs caused by susceptible bacteria. 
• Treatment of skin and soft tissue infections: gatifloxacin can be used to treat skin and soft tissue infections caused by susceptible bacteria. 
• Treatment of eye infections: gatifloxacin eye drops are used to treat conjunctivitis and corneal ulcers.