Geminox

Approved indications

• Acute bacterial exacerbation of chronic bronchitis (ABECB) — in adults caused by susceptible strains of Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae.
• Community-acquired pneumonia (CAP) — mild to moderate cases in adults due to susceptible bacteria, including S. pneumoniae, H. influenzae, Klebsiella pneumoniae, Mycoplasma pneumoniae, Chlamydophila pneumoniae.

Clinically accepted / off-label uses

• Complicated urinary tract infections (off-label, based on susceptibility and local guidelines).
• Prophylaxis or treatment in certain high-risk patients for respiratory infections, under specialist supervision.

Adults

• ABECB: 320 mg orally once daily for 5–7 days.
• CAP: 320 mg orally once daily for 7 days.
• Take with or without food; swallow tablets whole, do not crush or split.

Elderly

• No routine dose adjustment required; monitor renal and hepatic function, as adverse effects may be more pronounced.

Renal impairment

• Mild to moderate (CrCl ≥30 mL/min): no adjustment needed.
• Severe (CrCl <30 mL/min): use with caution; limited data; monitor renal function.

Hepatic impairment

• Mild to moderate: no dose adjustment required.
• Severe: use with caution; monitor liver enzymes.

Pediatrics

• Safety and efficacy not established for patients under 18 years old.

Gemifloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, enzymes critical for bacterial DNA replication, transcription, repair, and recombination. By binding to these enzymes, gemifloxacin prevents supercoiling and relaxation of bacterial DNA, leading to inhibition of DNA synthesis and bacterial cell death. It exhibits bactericidal activity against a broad spectrum of gram-positive and gram-negative pathogens.

• Absorption: Rapid oral absorption; bioavailability ~71–75%.
• Time to peak (Tmax): 1–2 hours after oral administration.
• Distribution: Widely distributed in tissues, including lungs, bronchial mucosa, and epithelial lining fluid; moderate protein binding (~60–65%).
• Metabolism: Partially metabolized in the liver; minor metabolism by CYP1A2.
• Elimination: Primarily excreted unchanged in urine (~20–25%) and feces (~60–65%).
• Half-life: Approximately 7–10 hours, allowing once-daily dosing.
• Steady-state: Reached in 2–3 days of once-daily dosing.

• Pregnancy: Animal studies have shown fetal harm; human data are limited. Use only if clearly needed and if potential benefits outweigh risks.
• Lactation: Excreted in breast milk in small amounts; breastfeeding is not recommended during therapy due to potential adverse effects on the infant.

• Primary class: Antibiotic
• Subclass: Fluoroquinolone

• Known hypersensitivity to gemifloxacin, other fluoroquinolones, or excipients.
• History of tendinitis or tendon rupture related to fluoroquinolone therapy.
• Concurrent use of tizanidine (due to significant hypotensive interactions).
• Pediatric and adolescent patients under 18 years (due to risk of musculoskeletal toxicity).

• Tendinitis and tendon rupture: Increased risk in patients >60 years, corticosteroid users, or kidney/liver transplant recipients. Discontinue if tendon pain/swelling occurs.
• Peripheral neuropathy: Can cause irreversible nerve damage; discontinue immediately if symptoms appear.
• Central nervous system effects: May cause dizziness, confusion, hallucinations, seizures; use with caution in patients with CNS disorders.
• QT prolongation: Caution in patients with arrhythmias, electrolyte imbalances, or on QT-prolonging drugs.
• Hepatic dysfunction: Monitor liver enzymes periodically.
• Clostridioides difficile-associated diarrhea: Discontinue therapy if severe diarrhea occurs.

Common

• Gastrointestinal: nausea, diarrhea, abdominal pain.
• Central nervous system: headache, dizziness.
• Dermatologic: rash, pruritus.

Serious / rare

• Tendon rupture (Achilles, shoulder, hand).
• Peripheral neuropathy.
• QT interval prolongation, arrhythmias.
• Hepatotoxicity.
• Severe hypersensitivity reactions, including anaphylaxis.

Onset

• GI effects: typically within first few days.
• Tendinopathy: may appear during or weeks after therapy.

• Tizanidine: Contraindicated; severe hypotension may occur.
• Antacids, sucralfate, iron, multivitamins: May reduce absorption; separate by 2–4 hours.
• Warfarin: May enhance anticoagulant effect; monitor INR.
• QT-prolonging agents: Additive risk of arrhythmias.
• CYP1A2 substrates: Gemifloxacin may inhibit metabolism slightly; monitor drugs with narrow therapeutic index.

• CAP & ABECB: Short-course (5–7 days) therapy preferred over longer regimens to reduce resistance and adverse events.
• Fluoroquinolone caution: FDA and EMA recommend avoiding fluoroquinolones for uncomplicated infections when alternatives exist due to risks of tendon, neurological, and psychiatric adverse effects.
• Pediatric use: Still contraindicated in under 18 due to musculoskeletal toxicity risk.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and light.
• Keep in the original container, tightly closed.
• Keep out of reach of children.