Ofloxacin
Ofloxacin
Generic Name
Ofloxacin
Mechanism
- Inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, preventing DNA supercoiling and segregation during replication.
- Membrane penetration: Unlike some fluoroquinolones, ofloxacin is lipophilic enough to treat infections in the respiratory tract, skin, and abdomen with adequate tissue penetration.
- Rapid bactericidal activity: Characteristic of fluoroquinolones — leads to bacterial cell death by generating double‑strand DNA breaks.
Pharmacokinetics
| Property | Value |
| Absorption | Excellent; ~67–78 % oral bioavailability; unaffected by food. |
| Distribution | 4–5 L kg⁻¹; good penetration into CSF (~30 % of plasma), respiratory secretions, and skin. |
| Metabolism | Minimal hepatic metabolism; primarily excreted unchanged. |
| Excretion | Renal (≈90 % unchanged); clearance 2.0–2.2 L h⁻¹; terminal half‑life 4 h (IV) – 7 h (PO). |
| Special Populations | Augmented renal clearance in sepsis may increase dose; caution in patients with renal insufficiency (dose adjustment). |
Indications
- Upper respiratory tract infections: Acute pharyngitis, sinusitis, exacerbations of COPD, bronchitis.
- Lower respiratory tract infections: Community‑acquired pneumonia, pyelonephritis.
- Skin and soft‑tissue infections: Cellulitis, impetigo, excoriations.
- Genitourinary tract: Clinical‑stage cystitis, uncomplicated urethritis.
- Intra‑abdominal infections: Peritonitis, obstructive abscesses.
- Miscellaneous: Uncomplicated prostatitis (short course); ocular infections (e.g., acute bacterial conjunctivitis — eye drops).
Contraindications
- Contraindications
- Hypersensitivity to fluoroquinolones or any component.
- Known tendon disorders (tendinitis, tendon rupture).
- Warnings
- Adverse CNS effects: seizures, tremor, confusion, hallucination.
- QT‑interval prolongation: risk ↑ with concurrent drugs that prolong QT (e.g., azithromycin, cisapride).
- Neuro‑toxicity: rare peripheral neuropathy, radiculopathy.
- Taste alterations: metallic taste, dysgeusia.
- Risk of tendinopathy / tendon rupture: especially in patients >60 yr, with concomitant steroids or organ transplant.
- Children and adolescents: avoid due to cartilage/bone toxicity.
Dosing
| Indication | Dose & Form | Route | Duration |
| Urinary Tract Infection | 200–400 mg BID | PO or IV | 6–14 days |
| Upper Respiratory Tract | 200 mg BID | PO | 5 days |
| Lower Respiratory Tract | 400 mg BID | PO or IV | 7–14 days |
| Skin / Soft‑tissue | 200–400 mg BID | PO | 7–10 days |
| Intra‑abdominal | 400 mg BID | PO | 5–7 days |
| Ocular | 0.5 % eye drops, q6h | Topical | 4 days |
| Short‑course for prostatitis | 200 mg BID | PO | 3–5 days |
Adjustment: For CrCl < 30 mL min⁻¹, reduce dose to 200 mg BID or 200 mg q48h IV.
Adverse Effects
- Common
- GI: nausea, vomiting, diarrhea, dyspepsia.
- CNS: headache, dizziness, insomnia.
- Rash, pruritus, photosensitivity.
- Serious
- Tendinopathy / tendon rupture (especially Achilles).
- QT prolongation → ventricular arrhythmias.
- Severe CNS events: seizures, acute myoclonic jerks.
- Peripheral neuropathy: paresthesias, obstructive radiculopathies.
- Allergic reactions: anaphylaxis, urticaria.
- Severe GI: colitis with *Clostridioides difficile* (antibiotic‑associated diarrhea).
Monitoring
- Renal function: CrCl/Creatinine phosphate pre‑treatment and every 2 weeks for >30 days.
- Electrolytes: Monitor if using with other QT‑prolonging medications.
- Serious adverse events: Watch for tendon pain or swelling.
- Blood glucose: In diabetic patients, monitor hyperglycemia; fluoroquinolones can worsen glucose control.
- QT interval: Baseline ECG for patients >60 yr or with multiorgan disease.
Clinical Pearls
- Avoid in pediatrics: Fluoroquinolone use is linked with irreversible cartilage damage; reserved for life‑saving situations only.
- Sexual tension: A rare but notable effect—some patients report altered sexual function; patient education may reduce discontinuation.
- Drug interactions to avoid: Calcium‑rich foods or supplements (displace absorption) and agents that raise plasma levels leading to QT prolongation (e.g., macrolides, ibutilide).
- Rapid eradication of Pseudomonas aeruginosa**: Use 400 mg po BID or IV; pathophysiology dictates high intrapleural Cmax for effective neutrophil function.
- Mechanistic synergy: Combining ofloxacin with β‑lactams can provide post‑antibiotic effect due to overlapping inhibition of DNA synthesis.
- Rapid onset: For empiric therapy in moderate sepsis, 400 mg IV q12 h maximizes plasma peak within 1–2 h for prompt bactericidal effect.
- Photo‑sensitivity: Educate patients to avoid UV exposure and use sunscreen during therapy to prevent rash or burns.
- Duration‑related risk: Prolonged courses (>10 days) disproportionately increase tendon rupture risk.
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• *This drug card combines evidence‑based data and practice guidelines for quick reference in clinical decision‑making. Always refer to local formularies and institutional protocols before prescribing.*