Mechanism of Action of Gatifloxacin
Gatifloxacin is a synthetic broad-spectrum 8-methoxyfluoroquinolone antibacterial agent for oral or intravenous administration. is bactericidal and its mode of action depends on blocking of bacterial DNA replication by binding itself to an enzyme called DNA gyrase, which allows the untwisting required to replicate one DNA double helix into two. Notably the drug has 100 times higher affinity for bacterial DNA gyrase than for mammalian. Gatifloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and Gram-negative bacteria. It should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.
or
The bactericidal action of Gatifloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination.
Indications of Gatifloxacin
- Ophthalmic Surgery
- Conjunctivitis
- Conjunctivitis, Bacterial
- For the treatment of bronchitis,
- Sinusitis,
- Community-acquired pneumonia,
- Skin infections (abscesses, wounds) caused by S. pneumoniae, H. influenzae, S. aureus, M. pneumoniae, C. pneumoniae, L. pneumophila, S. pyogenes
- For the treatment of bronchitis, sinusitis, community-acquired pneumonia, and skin infections (abscesses, wounds) caused by S. pneumoniae, H. influenzae, S. aureus, M. pneumoniae, C. pneumoniae, L. pneumophila, S. pyogenes
- Infections when due to gatifloxacin-susceptible pathogens: community-acquired pneumonia (mild to moderate) and complicated urinary tract infections (excluding prostatitis and epididymitis.
Contra-Indications of Gatifloxacin
- History of severe hypersensitivity (e.g. anaphylactic reaction) to any other type of beta-lactam antibacterial agent (penicillins, monobactams, and carbapenems).
- Hemolytic anemia
- Liver problems
- Interstitial nephritis
- Subacute cutaneous lupus erythematosus
- Systemic lupus erythematosus
- use should be avoided in pregnant or lactating women, and in children with developing teeth because they may result in permanent staining (dark yellow-gray teeth with a darker horizontal band that goes across the top and bottom rows of teeth), and possibly affect the growth of teeth and bones.
Dosage of Gatifloxacin
Strengths: 0.5%; 0.3%
Bacterial Conjunctivitis
0.3% solution
- Days 1 and 2: Instill 1 drop in the affected eye(s) every 2 hours while awake, up to 8 times a day.
- Days 3 through 7: Instill 1 drop in the affected eye(s) up to 4 times a day while awake.
0.5% solution
- Day 1: Instill 1 drop in the affected eye(s) every 2 hours while awake, up to 8 times a day.
- Days 2 through 7: Instill 1 drop in the affected eye(s) 2 to 4 times a day while awake.
Bacterial Conjunctivitis
1 year or older, 0.3% solution
- Days 1 and 2: Instill 1 drop in the affected eye(s) every 2 hours while awake, up to 8 times a day.
- Days 3 through 7: Instill 1 drop in the affected eye(s) up to 4 times a day while awake.
0.5% solution
- Day 1: Instill 1 drop in the affected eye(s) every 2 hours while awake, up to 8 times a day.
- Days 2 through 7: Instill 1 drop in the affected eye(s) 2 to 4 times a day while awake.
Pediatric Bacterial Conjunctivitis
1 year or older; 0.3% solution
- Days 1 and 2: Instill 1 drop in the affected eye(s) every 2 hours while awake, up to 8 times a day.
- Days 3 through 7: Instill 1 drop in the affected eye(s) up to 4 times a day while awake.
0.5% solution
- Day 1: Instill 1 drop in the affected eye(s) every 2 hours while awake, up to 8 times a day.
- Days 2 through 7: Instill 1 drop in the affected eye(s) 2 to 4 times a day while awake.
Side Effects of Gatifloxacin
The most common side effects
- allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
- Eye irritation
- eye pain
- eye redness
- pain, swelling, irritation where injected
- Abdominal pain
- sweating
- skin color change, mild diarrhea
- mild nausea
- loss of appetite
- vaginal discharge and itching
- swelling of feet or legs
- chest pain
- constipation
- a cough
- diarrhea or loose stools
- difficulty with breathing
- dizziness
- heartburn
More common
- Abdominal or stomach pain, discomfort, or tenderness
- chills or fever
- a headache, severe and throbbing
- joint or back pain
- muscle aching or cramping
- muscle pains or stiffness
- chest pressure or squeezing pain in the chest
- excessive sweating
- feeling of heaviness, pain, warmth and/or swelling in a leg or in the pelvis
- sudden tingling or coldness in an arm or leg
- sudden slow or difficult speech
- sudden drowsiness or need to sleep
- fast breathing
- sharp pain when taking a deep breath
- fast or slow heartbeat
- coughing up blood
- decreased amount of urine
Rare
- Anxiety
- change in vision
- seizures
- tremors
- weight loss
- chest pain or tightness
- confusion
- cough
- Agitation
- blurred vision
- chest pain or discomfort
- convulsions
- extra heartbeats
- hallucinations
- headache
- irritability
- lightheadedness
- mood or mental changes
- muscle pain or cramps
Drug Interactions of Gatifloxacin
Gatifloxacin may interact with following drugs, supplements, & may change the efficacy of drugs
- antacids that contain aluminum, calcium, or magnesium
- birth control medications
- bismuth subsalicylate
- calcium supplements
- digoxin
- Rosuvastatin
- Duloxetine
- Albuterol
- Topiramate
- Carbamazepine
- Vitamin D3 (cholecalciferol)
- Alprazolam
- Cetirizine
- insulin
- iron supplements
- penicillin
- vitamin A derivatives (e.g. isotretinoin)
- warfarin
- zinc sulfate or gluconate
Pregnancy & Lactation of Gatifloxacin
FDA Pregnancy Category C
There are no data available on gatifloxacin ophthalmic use in pregnancy to inform a drug-associated risk. However, animal data have shown that administration of oral gatifloxacin throughout organogenesis and during late gestation through lactation did not produce adverse maternal, fetal, or neonatal effects at clinically relevant doses.
There are no data available regarding the presence of gatifloxacin in human milk, the effect of gatifloxacin on breastfeeding infants, or the effect of gatifloxacin on milk production. Animal data have shown that gatifloxacin is excreted in breast milk following oral administration;
