GATIFLOXACIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for GATIFLOXACIN (GATIFLOXACIN).
Gatifloxacin inhibits bacterial DNA gyrase and topoisomerase IV, enzymes essential for DNA replication, transcription, repair, and recombination.
| Metabolism | Gatifloxacin is minimally metabolized; ~70% excreted unchanged in urine via glomerular filtration and tubular secretion; minor hepatic metabolism (<1%) to ethylenediamine and N-acetyl metabolites. |
| Excretion | Primarily renal excretion (70-87% unchanged in urine) via glomerular filtration and tubular secretion; ~10% biliary/fecal |
| Half-life | Terminal elimination half-life 7-14 hours (mean ~10 hours in healthy adults); prolonged in renal impairment (up to 40 hours with CrCl <30 mL/min) |
| Protein binding | ~20% bound to serum proteins (primarily albumin) |
| Volume of Distribution | 1.3-2.5 L/kg (mean ~1.8 L/kg), indicating extensive tissue penetration including lungs, kidneys, prostate, and CSF (with inflammation) |
| Bioavailability | Oral: 96% (range 88-107%) |
| Onset of Action | Oral: 1-2 hours to peak plasma concentration; IV: immediate, with peak at end of infusion; Clinical effect typically apparent within 24 hours |
| Duration of Action | Concentration-dependent killing; duration ~12-24 hours based on MIC; once-daily dosing maintains efficacy for susceptible organisms; half-life supports 24-hour dosing interval |
400 mg orally or intravenously once daily
| Dosage form | SOLUTION/DROPS |
| Renal impairment | CrCl 40-59 mL/min: 400 mg once daily; CrCl 20-39 mL/min: 200 mg once daily; CrCl <20 mL/min: 200 mg every 48 hours; hemodialysis or CAPD: 200 mg every 48 hours |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment; not studied in severe impairment |
| Pediatric use | Not recommended for pediatric patients due to risk of arthropathy; if required, 10 mg/kg oral or IV every 12 hours (max 400 mg/day) only for specific indications approved by specialist |
| Geriatric use | Dose adjustment based on renal function; monitor for QT prolongation and tendon adverse effects; no specific age-based adjustment if CrCl ≥60 mL/min |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for GATIFLOXACIN (GATIFLOXACIN).
| Breastfeeding | Excreted in breast milk; M/P ratio 1.5. Potential for arthropathy and other adverse effects in nursing infants. Avoid breastfeeding or discontinue drug; consider alternative agents with better safety profile. |
| Teratogenic Risk | Category C: Animal studies show fetal toxicity (increased skeletal variations, delayed ossification) at clinically relevant doses. No adequate human studies. Risk of arthropathy in immature animals. Avoid in first trimester if possible; use only if benefit outweighs risk. |
■ FDA Black Box Warning
Gatifloxacin is associated with an increased risk of tendinitis and tendon rupture in all ages. Risk is further increased in patients over 60 years old, those taking corticosteroids, and those with kidney, heart, or lung transplants.
| Serious Effects |
["Known hypersensitivity to gatifloxacin or any fluoroquinolone","History of tendinopathy or tendon rupture with fluoroquinolones","Pregnancy","Lactation","Use in children under 18 years (except for approved indications)","Concurrent use with Class IA or III antiarrhythmics (QT prolongation risk)","Uncorrected electrolyte disturbances (e.g., hypokalemia, hypomagnesemia)"]
| Precautions | {"Tendon damage":"Increased risk of tendinitis and tendon rupture, especially in elderly, patients on corticosteroids, and transplant recipients.","Peripheral neuropathy":"May occur rapidly and become irreversible.","CNS effects":"May cause seizures, dizziness, confusion, and increased intracranial pressure.","QT prolongation":"Avoid in patients with known QTc prolongation, electrolyte disturbances, or those on other QT-prolonging drugs.","Dysglycemia":"Can cause both hypoglycemia and hyperglycemia; use with caution in diabetic patients.","Photosensitivity":"Avoid excessive sunlight/UV exposure.","Avoid in myasthenia gravis":"May exacerbate muscle weakness.","Resistance":"Use only for infections proven or strongly suspected to be caused by bacteria."} |
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| Fetal Monitoring |
| Monitor for maternal adverse effects: gastrointestinal disturbance, CNS effects (dizziness, headache), hypoglycemia (especially in diabetics), QTc prolongation (ECG if risk factors). Fetal ultrasound if exposure during pregnancy for skeletal development. |
| Fertility Effects | No evidence of impaired fertility in animal studies at therapeutic doses. Theoretical risk of altered microbiota affecting fertility; not clinically significant. |