1. Clinical Overview
Levofloxacin is a broad-spectrum, third-generation fluoroquinolone antibiotic. It is the pure (-)-(S)-enantiomer of the racemic drug ofloxacin, offering enhanced antibacterial activity and a favorable pharmacokinetic profile. It is bactericidal and works by inhibiting bacterial DNA gyrase and topoisomerase IV, enzymes critical for DNA replication, transcription, repair, and recombination. It is widely used in the Indian healthcare setting for treating a variety of community-acquired and hospital-acquired bacterial infections.
| Onset | Duration | Bioavailability |
|---|---|---|
| Rapid absorption; peak plasma concentrations (Tmax) achieved within 1-2 hours post oral dose. | Approximately 24 hours, supporting once-daily dosing due to its long half-life. | Approximately 99% after oral administration, indicating near-complete absorption. |
2. Mechanism of Action
Levofloxacin exerts its bactericidal effect by inhibiting two essential bacterial type II topoisomerase enzymes: DNA gyrase (primarily in Gram-negative bacteria) and topoisomerase IV (primarily in Gram-positive bacteria). This inhibition interferes with DNA supercoiling, replication, transcription, and repair, leading to double-stranded DNA breaks and rapid bacterial cell death.
3. Indications & Uses
- Acute Bacterial Exacerbation of Chronic Bronchitis (ABECB)
- Community-Acquired Pneumonia (CAP)
- Uncomplicated Skin and Skin Structure Infections (uSSSI)
- Complicated Skin and Skin Structure Infections (cSSSI)
- Acute Bacterial Sinusitis (ABS)
- Complicated Urinary Tract Infections (cUTI) including Pyelonephritis
- Uncomplicated Urinary Tract Infections (uUTI)
- Chronic Bacterial Prostatitis
4. Dosage & Administration
Adult Dosage: 500 mg orally or IV once every 24 hours. Duration varies: 7-14 days for CAP/sinusitis, 10-14 days for cUTI/pyelonephritis, 28 days for chronic bacterial prostatitis.
Administration: Can be taken with or without food. Tablets should be swallowed whole with a full glass of water. Maintain adequate hydration. Do not take with dairy products, calcium-fortified juices, or antacids containing magnesium/aluminum, calcium, iron, or zinc; separate by at least 2 hours before or 4 hours after levofloxacin dose.
5. Side Effects
Common side effects may include:
- Nausea
- Diarrhea
- Headache
- Insomnia
- Dizziness
- Constipation
- Abdominal pain
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Antacids (Al, Mg), Sucralfate, Multivitamins with Zinc/Iron, Dairy Products | Form chelation complexes, drastically reducing levofloxacin absorption and bioavailability. | Major |
| Corticosteroids (e.g., Prednisolone) | Concomitant use increases the risk of tendon rupture, especially in elderly. | Major |
| NSAIDs (e.g., Ibuprofen, Diclofenac) | May increase the risk of CNS stimulation and seizures. | Moderate |
| Oral Anticoagulants (Warfarin) | May enhance anticoagulant effect; monitor INR closely. | Moderate |
| Antiarrhythmics (Amiodarone, Sotalol), Antipsychotics, TCAs, Macrolides | Additive effect on QT interval prolongation, increasing arrhythmia risk. | Major |
| Theophylline | Levofloxacin may inhibit theophylline metabolism, increasing theophylline levels and toxicity risk. | Moderate |
| Cyclosporine | May increase serum creatinine; monitor renal function. | Moderate |
| Probenecid | Reduces renal tubular secretion of levofloxacin, increasing its serum levels and half-life. | Moderate |
| Insulin, Oral Hypoglycemics | May cause hyperglycemia or hypoglycemia; monitor blood glucose. | Moderate |
7. Patient Counselling
- DO complete the full course of therapy even if you feel better.
- DO drink plenty of fluids to maintain hydration.
- DO take the tablet at least 2 hours before or 4 hours after taking antacids, iron, calcium, or zinc supplements.
- DO inform your doctor immediately if you experience tendon pain, swelling, or inflammation, especially in the ankle, shoulder, or hand.
- DONT skip doses.
- DONT crush or chew the tablet.
- DONT share your medication with others.
8. Toxicology & Storage
Overdose: Symptoms may include CNS excitation (seizures, confusion, dizziness), nausea, vomiting, prolongation of the QT interval, and renal impairment. Erosion of gastrointestinal mucosa may occur.
Storage: Store below 30°C, in a cool, dry place. Protect from light and moisture. Keep out of reach of children. Do not use after the expiry date printed on the pack.