GEMIFLOXACIN MESYLATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for GEMIFLOXACIN MESYLATE (GEMIFLOXACIN MESYLATE).
Inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, blocking DNA replication and transcription.
| Metabolism | Minimal hepatic metabolism; primarily excreted unchanged in urine via glomerular filtration and tubular secretion. |
| Excretion | Renal: ~61% as unchanged drug, ~7% as glucuronide; Fecal/biliary: ~28% as unchanged drug and metabolites. |
| Half-life | Terminal elimination half-life 7–9 hours (mean 8.2 h) in healthy adults; prolonged in renal impairment (e.g., 15–22 h in severe renal impairment). |
| Protein binding | ~60% bound to serum proteins (primarily albumin). |
| Volume of Distribution | Apparent Vd 4–5 L/kg (mean 4.7 L/kg), indicating extensive tissue penetration (e.g., lung, sinuses, urine). |
| Bioavailability | Oral: ~71% absolute bioavailability; absorption unaffected by food. |
| Onset of Action | Oral: Clinical effect within 1–2 hours after absorption. |
| Duration of Action | Dosing interval of 24 hours due to concentration-dependent bactericidal activity; post-antibiotic effect (PAE) of 2–6 hours for Gram-positive and Gram-negative organisms. |
320 mg orally once daily for 7-14 days
| Dosage form | TABLET |
| Renal impairment | CrCl 40-60 mL/min: 320 mg daily; CrCl <40 mL/min: 160 mg daily; hemodialysis: 160 mg daily after dialysis |
| Liver impairment | No adjustment required for mild-moderate hepatic impairment; safety in severe impairment not established |
| Pediatric use | Not recommended for use in patients <18 years of age |
| Geriatric use | Caution due to increased risk of tendonitis and tendon rupture; monitor renal function; no specific dose adjustment except based on renal function |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for GEMIFLOXACIN MESYLATE (GEMIFLOXACIN MESYLATE).
| Breastfeeding | Gemifloxacin is excreted into human breast milk; milk-to-plasma ratio is approximately 0.7 in animal studies. Concentration in breast milk is low but may cause adverse effects in nursing infants such as diarrhea, candidiasis, or theoretical risk of arthropathy. Use only if benefits outweigh risks; consider alternative antibiotics with better safety profile during breastfeeding. |
| Teratogenic Risk | Teratogenic risk in humans is not fully established due to limited data. In animal studies, gemifloxacin did not show teratogenicity at doses up to 4 times the human exposure. However, fluoroquinolones are generally avoided in pregnancy due to potential arthropathy in juvenile animals. In first trimester, caution warranted due to risk of spontaneous abortion associated with some fluoroquinolones; in second and third trimesters, potential for fetal cartilage damage cannot be excluded. |
■ FDA Black Box Warning
Increased risk of tendinitis and tendon rupture, particularly in patients over 60, those on corticosteroids, and organ transplant recipients. Fluoroquinolones may exacerbate muscle weakness in myasthenia gravis patients. Risk of peripheral neuropathy, CNS effects (including seizures), and phototoxicity.
| Serious Effects |
Hypersensitivity to gemifloxacin or any fluoroquinolone; use in pediatric patients (<18 years) except for specific indications; use in patients with known QT prolongation or uncorrected electrolyte disturbances; concomitant use with Class IA or III antiarrhythmics.
| Precautions | Tendon damage, peripheral neuropathy, CNS effects (dizziness, seizures), QT prolongation, photosensitivity, hypersensitivity reactions, Clostridioides difficile-associated diarrhea, blood glucose disturbances in diabetics, renal impairment requires dose adjustment. |
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| Fetal Monitoring | Monitor for maternal adverse effects including gastrointestinal disturbances, headache, dizziness, and rare tendonitis or tendon rupture. No specific fetal monitoring required, but ultrasound may be considered if fluoroquinolone exposure occurs during pregnancy to assess fetal development. |
| Fertility Effects | In animal studies, gemifloxacin did not impair fertility in rats at doses up to 300 mg/kg/day. No human data on fertility effects; however, fluoroquinolones are not known to significantly affect fertility. Theoretical concern for spermatotoxicity based on some animal studies with other quinolones, but not confirmed. |