Identification
Name Colistimethate
Accession Number DB01111 (APRD00885)
Type small molecule
Description Colistimethate is an antibiotic that has been shown to have bactericidal activity against aerobic gram-negative microorganisms. Colistimethate is particularly indicated when the infection is caused by sensitive strains of Pseudomonas aeruginosa.
Structure
Categories (*)
Molecular Weight 1634.87
Groups approved
Monoisotopic Weight 1633.588775306
Pharmacology
Indication For the treatment of acute or chronic infections due to sensitive strains of certain gram-negative bacilli, particularly Pseudomonas aeruginosa.
Mechanism of action Colistimethate is a surface active agent which penetrates into and disrupts the bacterial cell membrane. Colistimethate is polycationic and has both hydrophobic and lipophilic moieties. It interacts with the bacterial cytoplasmic membrane, changing its permeability. This effect is bactericidal. There is also evidence that polymyxins enter the cell and precipitate cytoplasmic components, primarily ribosomes.
Absorption Very poor absorption from gastrointestinal tract.
Protein binding Not Available
Biotransformation As 80% of the dose can be recovered unchanged in the urine, and there is no biliary excretion, it can be assumed that the remaining drug is inactivated in the tissues, however the mechanism is unknown.
Route of elimination Not Available
Toxicity Oral LD50 in rats is 5450 mg/kg. Overdosage with colistimethate can cause neuromuscular blockade characterized by paresthesia, lethargy, confusion, dizziness, ataxia, nystagmus, disorders of speech and apnea. Respiratory muscle paralysis may lead to apnea, respiratory arrest and death.
Affected organisms
  • Gram-negative bacilli
Interactions
Drug Interactions
Drug Mechanism of interaction
Amikacin Aminoglycosides may enhance the nephrotoxic effect of Colistimethate. Aminoglycosides may enhance the neuromuscular-blocking effect of Colistimethate. Due to the potential for additive or synergistic toxicities (including both nephrotoxicity and neuromuscular blockade) between colistimethate and the aminoglycoside antibiotics, this combination should be avoided whenever possible. If these agents must be used together, patients' renal and neuromuscular function should be monitored closely.
Amphotericin B Amphotericin B may enhance the nephrotoxic effect of Colistimethate. Due to the potential for additive or synergistic nephrotoxicity between colistimethate and other nephrotoxic drugs, such as amphotericin B, this combination should be avoided whenever possible. If these agents must be used together, patients' renal function should be monitored closely.
Atracurium Colistimethate may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. If possible, avoid concomitant use of these products. Monitor for deeper, prolonged neuromuscular-blocking effects (respiratory paralysis) in patients receiving concomitant neuromuscular-blocking agents and polymyxin antibiotics (e.g., colistimethate, polymyxin B).
Cisatracurium Besylate Colistimethate may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. If possible, avoid concomitant use of these products. Monitor for deeper, prolonged neuromuscular-blocking effects (respiratory paralysis) in patients receiving concomitant neuromuscular-blocking agents and polymyxin antibiotics (e.g., colistimethate, polymyxin B).
Gentamicin Aminoglycosides may enhance the nephrotoxic effect of Colistimethate. Aminoglycosides may enhance the neuromuscular-blocking effect of Colistimethate. Due to the potential for additive or synergistic toxicities (including both nephrotoxicity and neuromuscular blockade) between colistimethate and the aminoglycoside antibiotics, this combination should be avoided whenever possible. If these agents must be used together, patients' renal and neuromuscular function should be monitored closely.
Kanamycin Aminoglycosides may enhance the nephrotoxic effect of Colistimethate. Aminoglycosides may enhance the neuromuscular-blocking effect of Colistimethate. Due to the potential for additive or synergistic toxicities (including both nephrotoxicity and neuromuscular blockade) between colistimethate and the aminoglycoside antibiotics, this combination should be avoided whenever possible. If these agents must be used together, patients' renal and neuromuscular function should be monitored closely.
Neomycin Aminoglycosides may enhance the nephrotoxic effect of Colistimethate. Aminoglycosides may enhance the neuromuscular-blocking effect of Colistimethate. Due to the potential for additive or synergistic toxicities (including both nephrotoxicity and neuromuscular blockade) between colistimethate and the aminoglycoside antibiotics, this combination should be avoided whenever possible. If these agents must be used together, patients' renal and neuromuscular function should be monitored closely.
Pancuronium Colistimethate may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. If possible, avoid concomitant use of these products. Monitor for deeper, prolonged neuromuscular-blocking effects (respiratory paralysis) in patients receiving concomitant neuromuscular-blocking agents and polymyxin antibiotics (e.g., colistimethate, polymyxin B).
Rocuronium Colistimethate may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. If possible, avoid concomitant use of these products. Monitor for deeper, prolonged neuromuscular-blocking effects (respiratory paralysis) in patients receiving concomitant neuromuscular-blocking agents and polymyxin antibiotics (e.g., colistimethate, polymyxin B).
Streptomycin Aminoglycosides may enhance the nephrotoxic effect of Colistimethate. Aminoglycosides may enhance the neuromuscular-blocking effect of Colistimethate. Due to the potential for additive or synergistic toxicities (including both nephrotoxicity and neuromuscular blockade) between colistimethate and the aminoglycoside antibiotics, this combination should be avoided whenever possible. If these agents must be used together, patients' renal and neuromuscular function should be monitored closely.
Tobramycin Increased risk of nephrotoxicity
Vancomycin Additive nephrotoxic effects may occur. Consider alternate therapy or monitor for renal function during concomitant therapy.
Vecuronium Colistimethate may increase the neuromuscular blocking action of Vecuronium. Risk of respiratory depression and apnea. Consider alternate therapy or monitor for prolonged neuromuscular blocking effects, such as respiratory paralysis.
Food Interactions Not Available
bacterial outer membrane
Name bacterial outer membrane
Gene Name Not Available
Pharmacological action yes
Actions incorporation into and destabilization
References
  • Vaara M: Polymyxins and their novel derivatives. Curr Opin Microbiol. 2010 Oct;13(5):574-81. Epub 2010 Sep 24. - Pubmed
  • Soon RL, Nation RL, Cockram S, Moffatt JH, Harper M, Adler B, Boyce JD, Larson I, Li J: Different surface charge of colistin-susceptible and -resistant Acinetobacter baumannii cells measured with zeta potential as a function of growth phase and colistin treatment. J Antimicrob Chemother. 2011 Jan;66(1):126-33. Epub 2010 Nov 16. - Pubmed
  • Evans ME, Feola DJ, Rapp RP: Polymyxin B sulfate and colistin: old antibiotics for emerging multiresistant gram-negative bacteria. Ann Pharmacother. 1999 Sep;33(9):960-7. - Pubmed
DTHybrid score Not Available