What is Levofloxacin (Levofloxacin) used for and what is the typical dosage?

Levofloxacin: Indications and Dosing

Levofloxacin is a broad-spectrum fluoroquinolone antibiotic used primarily for respiratory tract infections, urinary tract infections, and skin/soft tissue infections, with standard dosing of 500 mg once daily for 7-10 days or 750 mg once daily for 5 days depending on the indication. 1

Primary Clinical Indications

Respiratory Tract Infections

Community-Acquired Pneumonia (CAP)

• 750 mg once daily for 5 days is the preferred regimen for CAP, providing equivalent efficacy to the traditional 500 mg for 10 days while maximizing concentration-dependent bacterial killing and improving compliance 2, 1
• For hospitalized patients with moderate CAP without Pseudomonas risk factors, levofloxacin can be used as monotherapy—a significant advantage over beta-lactams that require macrolide combination 2
• Provides comprehensive coverage for Streptococcus pneumoniae (including multi-drug resistant strains), Haemophilus influenzae, Moraxella catarrhalis, and atypical pathogens (Legionella, Mycoplasma, Chlamydophila) 2, 1
• For severe CAP requiring ICU care, levofloxacin 750 mg daily must be combined with a non-antipseudomonal cephalosporin (ceftriaxone or cefotaxime) 2
• If Pseudomonas aeruginosa is suspected, levofloxacin 750 mg must be combined with an antipseudomonal beta-lactam (ceftazidime or piperacillin-tazobactam), never used as monotherapy 2

Acute Bacterial Sinusitis

• 750 mg once daily for 5 days or 500 mg once daily for 10-14 days 1
• Both regimens demonstrate equivalent clinical success rates (91.4% vs 88.6%) 1

Acute Exacerbations of Chronic Bronchitis

• 500 mg once daily for 7 days 2, 1

Urinary Tract Infections

Acute Pyelonephritis

• 750 mg once daily for 5 days is appropriate when fluoroquinolone resistance in community uropathogens does not exceed 10% 3, 1
• If resistance exceeds 10%, an initial intravenous dose of ceftriaxone 1 g or consolidated aminoglycoside dose is recommended before starting levofloxacin 3

Complicated Urinary Tract Infections

• 750 mg once daily for 5 days 1
• Always obtain urine culture and susceptibility testing 3

Chronic Bacterial Prostatitis

• 500 mg once daily for 28 days 1

Skin and Soft Tissue Infections

Complicated Skin and Skin Structure Infections

• 750 mg once daily for 7-14 days (IV or oral) 1
• Surgical intervention (incision/drainage or debridement) is often required as an integral part of therapy 1

Uncomplicated Skin Infections

• 500 mg once daily for 7-10 days 1

Standard Dosing Regimens

Adults with Normal Renal Function (CrCl ≥50 mL/min)

• 250 mg, 500 mg, or 750 mg once daily depending on indication 1
• Can be administered without regard to food 1
• Oral formulation is bioequivalent to IV, allowing seamless transition between routes 2, 1

Renal Dose Adjustments

This is critical—levofloxacin is 80% renally cleared and requires dose modification in renal impairment 4, 1

• CrCl 20-49 mL/min: Initial dose of 750 mg, then 750 mg every 48 hours 1
• CrCl 10-19 mL/min: Initial dose of 750 mg, then 500 mg every 48 hours 1
• Hemodialysis or CAPD: Initial dose of 750 mg, then 500 mg every 48 hours (no supplemental doses needed after dialysis) 4, 1

Pediatric Dosing (≥6 months)

Fluoroquinolones are generally not recommended for routine pediatric use due to concerns about bone and cartilage growth effects, but may be considered when benefits outweigh risks 4

• Children 6 months to <5 years: 10 mg/kg divided every 12 hours (maximum 750 mg/day) 2, 4, 1
• Children 5-16 years: 10 mg/kg once daily (maximum 750 mg/day) 4, 1
• Adolescents with skeletal maturity: 500 mg once daily 2

Critical Drug Interactions and Administration

Levofloxacin must be administered at least 2 hours before or 2 hours after antacids, sucralfate, metal cations (iron), multivitamins with zinc, or didanosine 4, 1

• These agents containing divalent cations (calcium, magnesium, aluminum) markedly decrease fluoroquinolone absorption 4

Important Contraindications and Precautions

When NOT to Use Levofloxacin

• Avoid in pregnancy due to teratogenic effects 4, 5
• Do not use if patient had fluoroquinolone exposure within 90 days due to high resistance risk 2
• Never use as monotherapy for MRSA infections—inadequate coverage 2
• Levofloxacin should not be used as a first-line agent except when patients are intolerant of first-line drugs or for drug-resistant organisms 5

Common Adverse Effects

• Gastrointestinal symptoms (nausea, diarrhea): 0.5-1.8% 4, 5
• Neurologic effects (dizziness, insomnia): 0.5% 4
• Cutaneous reactions (rash, pruritus): 0.2-0.4% 4
• Serious but rare: tendinitis and tendon rupture, particularly with long-term use or concomitant corticosteroids 5

Treatment Duration Principles

Treatment should generally not exceed 8 days in responding patients 2, 4

• The 5-day, 750 mg regimen has been shown equally effective as 10-day courses for CAP and sinusitis while minimizing antibiotic exposure and resistance selection pressure 2, 1

Monitoring Requirements

• Assess clinical response within 48-72 hours by monitoring temperature normalization, respiratory rate, oxygen saturation, and ability to eat 2
• Maintain adequate hydration to prevent crystalluria 1
• For elderly patients: obtain baseline renal function (CrCl), ECG for QT interval, and review for drug interactions with corticosteroids or QT-prolonging medications 4