Colistin Dosing for Intermittent Hemodialysis
For adult patients on intermittent hemodialysis, administer a loading dose of 6-9 MIU CBA followed by a maintenance dose of 2 MIU CBA every 12 hours, with hemodialysis performed at the end of the dosing interval. 1
Loading Dose
- 6-9 MIU CBA should be administered to all patients, including those with renal dysfunction
- The loading dose is critical because colistin displays a relatively long half-life, and plasma concentrations remain sub-optimal for 2-3 days before reaching steady state without a loading dose 1
- This loading dose applies regardless of renal function status 1
Maintenance Dosing
- 2 MIU CBA every 12 hours is the recommended maintenance regimen 1
- This translates to 4 MIU CBA total daily dose on non-dialysis days
Timing of Hemodialysis
Critical timing consideration: Dialysis should be performed toward the end of a CMS dosage interval 1. This is because:
- CMS is extensively removed by hemodialysis, with approximately 30.6% of the administered dose recovered in dialysate 2
- Dialysis clearance of CMS is substantial at 4.26-5.67 L/h 2
- Colistin itself also undergoes dialysis clearance at approximately 3.99 L/h 2
Supplemental Dosing After Dialysis
Research evidence suggests that a supplemental dose of 1.5 MIU should be administered after each hemodialysis session 3. This means on dialysis days, patients would receive:
- Regular 2 MIU dose in the morning
- Regular 2 MIU dose in the evening (before dialysis)
- Supplemental 1.5 MIU after dialysis
- Total: 5.5 MIU on dialysis days
Important Caveats
Dosage Unit Conversion
Pay careful attention to dosage units to avoid medication errors 1, 4:
- 1 million IU = 80 mg CMS = 33 mg CBA
- Different countries and formulations may express doses differently
Monitoring Requirements
- Renal function must be closely monitored during colistin treatment 5, 4
- Acute kidney injury is one of the most important factors related to clinical failure and mortality 5
- Consider therapeutic drug monitoring where available 4
Target Concentrations
The goal is to maintain colistin plasma concentrations >2-3 mg/L to achieve adequate pharmacodynamic targets 3, 6:
- For systemic infections: fAUC/MIC >10
- For pulmonary infections: fAUC/MIC >50
Limitations of Monotherapy
For patients with preserved residual renal function or high MIC organisms (≥1.5 mg/L for systemic infections or ≥0.5 mg/L for pulmonary infections), even optimal dosing may not achieve adequate target attainment 3. In these cases, combination therapy should be strongly considered 4.