Moxifloxacin Dosing for Adults
The recommended dose of moxifloxacin for adults is 400 mg once daily, administered orally or intravenously, regardless of the indication being treated. 1
Standard Dosing
- 400 mg once every 24 hours is the universal adult dose across all approved indications 1
- This dose can be administered orally (tablet) or intravenously with no dosage adjustment needed when switching between routes 1
- Moxifloxacin can be taken with or without food, as absorption is not significantly affected 1, 2
Duration of Therapy by Indication
The 400 mg daily dose remains constant, but treatment duration varies by infection type 1:
- Community-acquired pneumonia: 7-14 days 1
- Uncomplicated skin/skin structure infections: 7 days 1
- Complicated skin/skin structure infections: 7-21 days 1
- Complicated intra-abdominal infections: 5-14 days 1
- Plague: 10-14 days (begin as soon as possible after suspected exposure) 3, 1
- Acute bacterial sinusitis: 10 days 1
- Acute bacterial exacerbation of chronic bronchitis: 5 days 1
Special Populations
- No dose adjustment required for renal impairment of any severity, as moxifloxacin has a balanced excretion system 1, 4, 2
- No dose adjustment required for hepatic impairment (mild to moderate), as drug levels are not significantly affected 1, 4, 2
- No dose adjustment required for elderly patients 1
Critical Administration Instructions
Moxifloxacin must be separated from multivalent cation-containing products to avoid absorption interference 1:
- Administer at least 4 hours before or 8 hours after antacids, sucralfate, multivitamins, iron, zinc, magnesium, aluminum, or didanosine products 1
- This timing is non-negotiable as these products markedly decrease fluoroquinolone absorption 3
Important Safety Considerations
While the dose remains 400 mg daily, prescribers should note 1:
- Doses above 400 mg/day have limited long-term safety data and are not recommended 3
- Moxifloxacin is associated with QT prolongation and should be avoided in patients with known QT prolongation, hypokalemia, hypomagnesemia, or those taking other QT-prolonging drugs 1
- The drug carries a boxed warning for disabling and potentially irreversible serious adverse reactions including tendinitis, tendon rupture, peripheral neuropathy, and CNS effects 1
- Reserve moxifloxacin for patients with no alternative treatment options for acute bacterial sinusitis and acute bacterial exacerbation of chronic bronchitis 1
Pharmacokinetic Profile Supporting Once-Daily Dosing
The 400 mg once-daily regimen is supported by favorable pharmacokinetics 4, 2:
- Peak concentration (Cmax) of approximately 3.2-4.5 mg/L achieved within 2 hours 4, 2
- Terminal elimination half-life of 12 hours supports once-daily dosing 4
- Excellent tissue penetration into respiratory tissues exceeds plasma concentrations 4, 5
- No involvement of cytochrome P450 metabolism minimizes drug interactions 4