Comparative Pharmacology
Head-to-head clinical analysis: COLY MYCIN M versus POLYMYXIN B SULFATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COLY MYCIN M versus POLYMYXIN B SULFATE.
COLY-MYCIN M vs POLYMYXIN B SULFATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Colistin acts as a cationic detergent, binding to and disrupting the bacterial cell membrane, leading to cell death. It is active primarily against gram-negative bacteria.
Polymyxin B sulfate binds to lipopolysaccharides (LPS) in the outer membrane of gram-negative bacteria, disrupting membrane integrity and causing cell death. It also has anti-endotoxin activity.
2.5 to 5 mg/kg/day of colistin base activity divided every 8-12 hours intravenously; alternatively, 1.25 to 2.5 mg/kg every 12 hours. For inhalation, 75 mg (1 million units) of colistimethate sodium in 3 mL normal saline nebulized twice daily.
1.5 to 2.5 mg/kg/day IV divided every 12 hours; maximum 2.5 mg/kg/day. For topical use, apply 0.1% to 0.25% (10,000 to 25,000 units/g) ointment or cream 1-4 times daily.
None Documented
None Documented
Terminal elimination half-life of colistin (active formed moiety) is approximately 3-4 hours in patients with normal renal function; prolonged to 3-4 days in end-stage renal disease. Half-life of CMS itself is shorter (~2 hours). Clinical context: Dosing adjustments are critical in renal impairment to avoid accumulation and neuro/nephrotoxicity.
Terminal elimination half-life is approximately 7-10 hours in adults with normal renal function. In patients with severe renal impairment (CrCl <30 mL/min), half-life may be prolonged to 2-3 days. Half-life is significantly extended in anuria (up to 48-72 hours). Clinically, dosing must be adjusted based on renal function and therapeutic drug monitoring is recommended.
Primarily renal (approximately 60-70% of colistin [formed from CMS] excreted unchanged in urine via glomerular filtration and tubular secretion); ~10-20% biliary/fecal as unchanged drug. Colistimethate sodium (CMS) is also renally cleared. In renal impairment, clearance is significantly reduced.
Primarily renal excretion of unchanged drug via glomerular filtration (approx. 60-70% of a dose is recovered in urine as active polymyxin B). A smaller fraction (approximately 10-20%) is eliminated via non-renal pathways (biliary/fecal) as unchanged drug and minor metabolites; biliary excretion accounts for <5%.
Category C
Category C
Polymyxin Antibiotic
Polymyxin Antibiotic