Colistineb (Colistimethate Sodium)

Colistineb is indicated for the treatment of serious infections caused by susceptible Gram‑negative organisms, particularly when other antibiotics are ineffective. It is commonly employed in specific clinical scenarios:

• Inhalation therapy for chronic lung infections in cystic fibrosis patients caused by Pseudomonas aeruginosa.
• Intravenous treatment of severe systemic infections such as bacteremia or sepsis due to multidrug‑resistant Gram‑negative bacteria.
• Intramuscular administration for localized infections when intravenous access is not feasible.
• Use as a salvage therapy for infections resistant to other antibiotic classes.
• Management of hospital‑acquired pneumonia caused by susceptible organisms.

Colistineb may cause a range of adverse effects, varying from mild to severe. Patients should be monitored for any signs of toxicity.

Common

• Nausea, vomiting, or loss of appetite.
• Diarrhea or abdominal cramping.
• Skin rash or pruritus at the injection site.
• Transient elevation of liver enzymes.
• Mild headache or dizziness.

Serious

• Nephrotoxicity leading to acute kidney injury.
• Neurotoxicity presenting as paresthesia, muscle weakness, or seizures.
• Severe allergic reactions, including anaphylaxis.
• Respiratory distress when administered via inhalation.
• Hematologic abnormalities such as leukopenia.

Colistineb should be used with caution and under professional guidance due to its potential toxicity profile. Important safety considerations include:

• Baseline and periodic assessment of renal function, especially in patients with pre‑existing kidney disease.
• Monitoring of neurological status for signs of neurotoxicity.
• Avoid use in patients with known hypersensitivity to polymyxin antibiotics.
• Dose adjustment may be required in elderly patients or those with hepatic impairment.
• Use only when culture and sensitivity data confirm susceptibility to colistimethate sodium.
• Pregnancy and lactation status should be evaluated, as safety data are limited.

Colistineb can interact with several other medications, influencing its efficacy or increasing toxicity risk.

Avoid

• Concurrent use of other nephrotoxic agents such as aminoglycosides, vancomycin, or non‑steroidal anti‑inflammatory drugs.
• Co‑administration with neuromuscular blocking agents, which may exacerbate muscle weakness.

Use with caution

• Loop diuretics, which may affect renal clearance.
• Drugs that prolong the QT interval, as electrolyte disturbances from colistimethate may increase arrhythmia risk.
• Immunosuppressants, requiring close monitoring of infection response.
• Antacids or supplements containing calcium or magnesium, which could alter absorption when given inhalationally.