Colistin Dosing for UTI with eGFR 56
For a patient with a UTI and eGFR of 56 mL/min, the recommended dose of colistin is 2.5-3.8 mg/kg/day divided into 2 doses per day. 1
Dosing Recommendations Based on Renal Function
- For patients with mild renal impairment (eGFR 50-79 mL/min), the appropriate colistin dose is 2.5-3.8 mg/kg/day divided into 2 doses 1
- A loading dose of 9 million international units (MIU) should be administered initially, regardless of renal function, to rapidly achieve therapeutic levels 2, 3
- One million IU of colistin is equivalent to 80 mg of colistimethate sodium (CMS) 2
- Colistin is administered as colistimethate sodium, which is an inactive prodrug 2
Administration Methods
- Intravenous administration can be done via direct intermittent administration (slowly inject half the total daily dose over 3-5 minutes every 12 hours) 1
- Alternatively, continuous infusion can be used after the initial loading dose 1
- A 4-hour infusion is suggested to optimize pharmacokinetic/pharmacodynamic properties 2
Monitoring and Safety Considerations
- Renal function should be closely monitored during colistin therapy as acute kidney injury is a significant factor related to clinical failure and mortality 4, 2
- In the studied patient population, deterioration of renal function during colistin therapy was observed in 8% of patients 5
- For UTIs specifically, colistin has shown high efficacy for treatment of complicated UTIs caused by multidrug-resistant organisms 6
Special Considerations for UTI Treatment
- Aminoglycoside monotherapy is indicated for urinary tract infections, but colistin is an appropriate alternative for multidrug-resistant organisms 4
- The suggested treatment duration for complicated urinary tract infection is 5-7 days 4
- For UTIs specifically, lower doses may be effective due to higher urinary concentrations of colistin compared to plasma levels 6
Common Pitfalls and Caveats
- Colistin doses often vary greatly among patients, and in patients with renal impairment, dosing is commonly not in accordance with guidelines 7
- Avoid underdosing in the initial phase of treatment - the loading dose is critical due to colistin's relatively long half-life 2, 3
- Balance potential antibacterial benefit against risk of nephrotoxicity by monitoring renal function regularly 4
- Colistin nephrotoxicity rarely requires renal replacement therapy 7
Remember that while the recommended dose is 2.5-3.8 mg/kg/day for a patient with eGFR 56 mL/min, clinical response and renal function should be monitored throughout the treatment course.