What to Check Before Administering Colistin
Before administering colistin, renal function must be assessed as it is a critical determinant for dosing and monitoring due to colistin's significant nephrotoxicity potential. 1, 2
Pre-Administration Assessment
Renal Function Evaluation
- Baseline renal function should be documented through serum creatinine and creatinine clearance calculation 1, 3
- Patients with impaired renal function require dose adjustments to prevent toxicity 3
- For patients on renal replacement therapy (RRT), specific dosing protocols should be followed 3
Medication History
- Check for concomitant nephrotoxic medications that may increase risk of acute kidney injury (AKI) 4
- Particular attention should be paid to NSAIDs, as they are a significant risk factor for colistin-induced nephrotoxicity 4
- Review for other potentially interacting medications, especially other antibiotics and neuromuscular blocking agents 5
Laboratory Parameters
- Assess serum albumin levels, as hypoalbuminemia is associated with increased risk of nephrotoxicity 4, 6
- Check hematocrit levels, as lower values have been associated with nephrotoxicity 6
Dosing Considerations
Loading Dose
- A loading dose of 9 million international units (MU) should be administered regardless of renal function to rapidly achieve therapeutic levels 1, 2
- This is equivalent to 5 mg/kg of colistin base activity 2
Maintenance Dose
- For patients with normal renal function: 4.5 MU every 12 hours 1, 2
- For patients with impaired renal function: dose must be adjusted according to creatinine clearance 3
- For patients on continuous renal replacement therapy: at least 9 million IU/day 3
- For patients on intermittent hemodialysis: 2 million IU every 12 hours with a normal loading dose 3
Maximum Dose Limitations
- Maximum daily dose should not exceed 5 mg/kg/day with normal renal function 5
Patient Monitoring Plan
Renal Function Monitoring
- Establish a schedule for regular monitoring of renal function during treatment 1, 2
- Be vigilant for signs of acute kidney injury, which is reversible upon discontinuation 5, 7
Neurological Monitoring
- Assess for neurological side effects including circumoral paresthesia, tingling of extremities, vertigo, dizziness, and slurred speech 5
- Warn patients not to drive vehicles or use hazardous machinery while on therapy 5
Special Considerations
- For patients with estimated glomerular filtration rate <60 mL/min/1.73 m², be particularly cautious with dosing as they are more susceptible to nephrotoxicity 6
- In patients with augmented renal clearance, standard dosing may be used, but monitor closely 8
- Watch for signs of Clostridium difficile-associated diarrhea, which can occur during treatment 5
Common Pitfalls to Avoid
- Failing to administer a loading dose, which is critical due to colistin's long half-life 2
- Not adjusting maintenance doses based on renal function 1, 3
- Overlooking concomitant use of nephrotoxic medications, especially NSAIDs 4
- Inadequate monitoring of renal function during treatment 1, 2
- Continuing the same dose despite development of acute kidney injury 5, 7