| Indication |
For the treatment of acute or chronic infections due to sensitive strains of certain gram-negative bacilli, particularly Pseudomonas aeruginosa. |
| Mechanism of action |
Colistin is a surface active agent which penetrates into and disrupts the bacterial cell membrane. Colistin 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 |
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