Colistin (PDF Version)
Polymyxin
Acinetobacter baumannii and Pseudomonas aeruginosa, Klebsiella spp., Enterobacter spp., Escherichia coli, Salmonella spp., Shigella spp., Citrobacter spp., Yersinia pseudotuberculosis, and Haemophilus influenzae
Colsitin disrupts bacterial cell membrane phospholipids
Peak:MIC and AUC:MIC ration correlate best with efficacy
Pharmacokinetics (150mg dose):
Cmax: 18mg//L; Tmax: 2 hours; Half-life: 2-3 hours
Kidneys: Nephrotoxicity
Other: Neurotoxicity, drug fever
Skin: Pruritis, dermatoses
GI: gastrointestinal upset
Hematologic: leucopenia, granulocytopenia
FDA Warning: Colistin in Nebulizer Solution
Dosing in adults: 2.5-5mg/kg/day divided q6-12h
Dosing in pediatrics: 2.5-5mg/kg/day divided q6-12h
Disease state based dosing:
Renal failure: CrCl > 50mL/min: Standard dosing
CrCl 10-50mL/min: 50% of normal dose
CrCl < 10 mL/min: 25% of the normal dose
Hepatic failure: No dosing changes recommended at this time.
Dosing during Continuous Renal Replacement Therapy
CVVH (Continuous venovenous hemofiltration): 2.5mg/kg IV q48h
CVVHD (Continuous venovenous hemodialysis): 2.5mg/kg IV q48h*
CVVHDF (Continuous venovenous hemodiafiltration) 2.5mg/kg IV q48h*
*A recent pharmacokinetic study suggests conventional dosing recommendations in CVVHD and CVVHDF are not appropriate in the critically ill and higher doses of 2-3 mg/kg IV q12h may be more appropriate. (Li J, et al. Antimicrob Agents Chemother 2005;49:4814-4815)
Note: CVVH is mainly for fluid removal alone. Many institutions will employ more CVVHD or CVVHDF which combine dialysis with fluid removal.
Contraindications/Warnings/Precautions:
Precautions: Renal impairment
Non-depolarizing neuromuscular blockers: may lead to additive neuromuscular blockade
Category C: Risk unknown. Human studies inadequate
Therapeutic: Culture and sensitivities, serum levels, signs and symptoms of infection, white blood cell count
Toxic: Nephrotoxicity (Serum creatinine, BUN)
Brand names/Manufacturer: Colymycin (various generic manufacturers worldwide)