What are the uses and dosing of moxifloxacin (a fluoroquinolone antibiotic)?

Uses and Dosing of Moxifloxacin

Moxifloxacin is indicated for the treatment of several bacterial infections at a standard dose of 400 mg once daily, with treatment duration varying by indication. 1

Approved Indications and Treatment Duration

Respiratory Tract Infections

• Community-Acquired Pneumonia (CAP)

  • Dose: 400 mg once daily
  • Duration: 7-14 days 2, 1
  • Moxifloxacin is recommended for initial empiric therapy of selected outpatients with CAP, though macrolides and doxycycline are generally preferred for uncomplicated infections 2
  • Can be used as monotherapy for patients with CAP admitted to a hospital ward 2

• Acute Bacterial Sinusitis

  • Dose: 400 mg once daily
  • Duration: 10 days 1
  • Should be reserved for patients who have no alternative treatment options due to potential serious adverse reactions 1

• Acute Bacterial Exacerbation of Chronic Bronchitis

  • Dose: 400 mg once daily
  • Duration: 5 days 1
  • Should be reserved for patients who have no alternative treatment options due to potential serious adverse reactions 1

Skin and Skin Structure Infections

• Uncomplicated Skin and Skin Structure Infections

  • Dose: 400 mg once daily
  • Duration: 7 days 1

• Complicated Skin and Skin Structure Infections

  • Dose: 400 mg once daily
  • Duration: 7-21 days 1

Intra-Abdominal Infections

• Complicated Intra-Abdominal Infections (cIAIs)
  • Dose: 400 mg once daily
  • Duration: 5-14 days 1
  • Recommended by IDSA/SIS guidelines as monotherapy for mild-to-moderate cIAIs in regions with low resistance rates 2, 3
  • Not recommended in regions with high rates of fluoroquinolone resistance (>20%) or ESBL-producing Enterobacteriaceae (>10%) 2, 3

Other Infections

• Plague
  • Dose: 400 mg once daily
  • Duration: 10-14 days 1
  • Studies were conducted in animals only 1

Antimicrobial Spectrum

Moxifloxacin has a broad spectrum of activity against:

• Gram-positive bacteria (including penicillin and macrolide-resistant Streptococcus pneumoniae)
• Gram-negative bacteria
• Atypical respiratory pathogens (Legionella, Mycoplasma, Chlamydophilia)
• Anaerobes 4, 5, 6

Important Safety Considerations

Boxed Warnings

Moxifloxacin carries FDA boxed warnings for serious adverse reactions including:

1. Tendinitis and tendon rupture
2. Peripheral neuropathy
3. Central nervous system effects
4. Exacerbation of myasthenia gravis 1

Contraindications

• Known hypersensitivity to moxifloxacin or other quinolones
• History of myasthenia gravis
• History of tendon disorders or peripheral neuropathy 1

QT Interval Prolongation

• Moxifloxacin can prolong the QT interval and should be avoided in:
  • Patients with known QT prolongation
  • Patients with ventricular arrhythmias including torsade de pointes
  • Patients with uncorrected hypokalemia or hypomagnesemia
  • Patients taking Class IA or Class III antiarrhythmic agents 1

Administration Considerations

• No dosage adjustment required for patients with renal impairment or mild hepatic impairment 1
• Should be taken at least 4 hours before or 8 hours after products containing multivalent cations (antacids, sucralfate, multivitamins) 1
• Available in both oral and intravenous formulations 4, 5

Clinical Pearls and Caveats

• Despite its broad spectrum, moxifloxacin should be used judiciously due to the risk of serious adverse effects
• Fluoroquinolone resistance is emerging in S. pneumoniae and varies geographically 2
• For community-acquired pneumonia, macrolides and doxycycline are generally preferred for uncomplicated infections 2
• For intra-abdominal infections, local resistance patterns should guide therapy choice 2, 3
• Discontinue immediately if patients experience tendon pain, peripheral neuropathy symptoms, or CNS effects 1

Moxifloxacin remains an important option for various bacterial infections, but its use should be balanced against the risk of adverse effects and the need for antimicrobial stewardship.