IV Moxifloxacin Dosing in Patients with GFR of 18
No dosage adjustment is necessary for IV moxifloxacin in patients with a GFR of 18 mL/min; the standard dose of 400 mg IV once daily should be administered. 1
Pharmacokinetic Considerations in Renal Impairment
- Moxifloxacin pharmacokinetics are not significantly altered in mild, moderate, severe, or end-stage renal disease 1
- The drug is primarily metabolized through the liver with only partial renal elimination, making it suitable for patients with impaired kidney function 2, 3
- Unlike many other antibiotics, moxifloxacin has a balanced system of excretion that does not require dosage adjustments in patients with renal impairment 3
Evidence Supporting Standard Dosing
- According to the FDA drug label, no dosage adjustment is necessary in patients with renal impairment, including those requiring hemodialysis or continuous ambulatory peritoneal dialysis 1
- Studies in patients with varying degrees of renal function show that while peak concentrations (Cmax) may be reduced by 21-28% in patients with moderate to severe renal impairment, the mean systemic exposure (AUC) is only increased by approximately 13% 1
- Research in critically ill patients with acute renal failure undergoing continuous venovenous haemodiafiltration demonstrated that moxifloxacin pharmacokinetics remained comparable to those in healthy subjects 4
Metabolite Considerations
- While the sulfate conjugate (M1) and glucuronide conjugate (M2) metabolites of moxifloxacin may accumulate in patients with renal impairment, these metabolites are not microbiologically active 1
- The clinical implications of increased exposure to these metabolites have not been shown to be significant 1, 2
Clinical Implications and Monitoring
- Moxifloxacin is generally well tolerated in patients with renal impairment 2
- Unlike other antibiotics that require significant dose adjustments in renal impairment (such as aminoglycosides or certain fluoroquinolones like levofloxacin), moxifloxacin maintains its standard dosing 5
- The lack of significant drug interactions makes moxifloxacin a suitable option for patients with renal impairment who may be on multiple medications 2
Comparison with Other Fluoroquinolones
- In contrast to moxifloxacin, levofloxacin requires dose adjustment in renal impairment, with recommendations for 750-1000 mg three times weekly (rather than daily) when GFR is <30 mL/min 5
- Studies directly comparing moxifloxacin and levofloxacin in patients with acute renal failure found that while levofloxacin required dosage reduction, moxifloxacin could be administered at standard doses 6
Practical Recommendations
- Administer the standard dose of 400 mg IV moxifloxacin once daily in patients with GFR of 18 mL/min 1, 3
- If the patient is receiving hemodialysis, the drug can be given at any time as it is not significantly removed by dialysis 1
- No additional post-dialysis dose is required, unlike many other antibiotics 1, 4