What are the uses and advantages of Colistin (Polymyxin E)?

From the Guidelines

Colistin is a crucial antibiotic for treating multidrug-resistant Gram-negative bacterial infections, and its use should be guided by the most recent evidence, which recommends a loading dose of 9 MU of colistin methanesulfonate (CMS) followed by 4.5 MU CMS twice a day as the maintenance dose in critically ill patients 1. The main advantages of colistin include its effectiveness against carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii, which are resistant to most other antibiotics. Colistin works by disrupting bacterial cell membranes, leading to cell death. Some key points to consider when using colistin include:

• The optimal dosage of colistin in pediatric patients remains uncertain, but the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) recommend a loading dose of 0.15 MU/kg of colistin in children followed by a maintenance dose of 0.075 MU/kg every 12 h 1.
• Pharmacodynamic studies in critically ill patients have shown that the optimal dose of colistin is 9 MU of colistin methanesulfonate (CMS) initially followed by 4.5 MU CMS twice a day as the maintenance dose 1.
• Close monitoring of kidney function is essential during treatment due to the risk of nephrotoxicity, and clinicians should weigh the benefits and risks of colistin therapy, especially in patients with acute kidney injury 1.
• The use of colistin-based combination therapy is controversial, and the decision to use it should be based on the individual patient's circumstances and the susceptibility of the infecting organism 1. Overall, colistin is a valuable antibiotic for treating multidrug-resistant Gram-negative bacterial infections, but its use requires careful consideration of the risks and benefits, as well as close monitoring of kidney function. The most recent evidence suggests that colistin-based treatment is recommended in DTR-PA infections, with a strong recommendation for monitoring renal function during colistin treatment 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Important: Colistimethate for Injection, USP is supplied in vials containing colistimethate sodium equivalent to 150 mg colistin base activity per vial. The dose of Colistimethate for Injection, USP should be 2. 5 to 5 mg/kg per day of colistin base in 2 to 4 divided doses for patients with normal renal function, depending on the severity of the infection.

The uses of colistin include the treatment of infections in adults and pediatric patients. The advantages of colistin are not explicitly stated in the label, but it can be inferred that colistin is effective against certain infections, particularly those caused by gram-negative bacteria.

• The dosage of colistin is based on the severity of the infection and the patient's renal function.
• The label provides guidance on dosage adjustments for patients with renal impairment 2. Key points about colistin use include:
• Administration via intravenous or intramuscular injection
• Dosage based on colistin base activity
• Reduction of dosage in patients with renal impairment The label does not provide information on the advantages of colistin compared to other antibiotics.

From the Research

Uses of Colistin

• Colistin is used to treat severe infections caused by multi-drug-resistant (MDR) Gram-negative bacteria, particularly in critically ill patients 3, 4.
• It is effective against MDR Acinetobacter baumannii-related pneumonia 3.
• Colistin can be administered intravenously, via inhalation for pneumonia/ventilator-associated pneumonia treatment, or by the intraventricular/intrathecal route for meningitis/ventriculitis treatment 4.

Advantages of Colistin

• Colistin is an effective option for the treatment of infections caused by MDR Gram-negative bacteria, with a low incidence of nephrotoxicity 5.
• High-dose colistin (>4.4 mg/kg/day) is independently associated with day 7 global cure in patients with bacteremia due to carbapenem-resistant Gram-negative bacilli 6.
• Combining intravenous and inhaled colistin may improve outcomes in patients with MDR Gram-negative infections 3.
• Colistin has a reliable role as a future antibiotic for the treatment of multi-resistant Gram-negative infections, and as an alternative to available antibiotics 7.

Key Findings

• Clinical cure was observed in 42.7% of patients treated with colistin for MDR Acinetobacter baumannii-related pneumonia 3.
• The minimum inhibitory concentration (MIC) of colistin is a significant predictor of bacterial cure, with lower MIC values associated with improved outcomes 5.
• Nephrotoxicity is a common side effect of colistin therapy, occurring in up to 53.7% of patients 3.