Colistimethate Sodium

Colistimethate sodium is a surface active agent which penetrates into and disrupts the bacterial cell membrane. It has been shown to have bactericidal activity against Aerobic gram-negative microorganisms e.g. Enterobacter aerogenes, E. coli, Klebsiella pneumoniae and Pseudomonas. Colistimethate is polycationic and has both hydrophobic and lipophilic moieties. It interacts with the bacterial cytoplasmic membrane, changing its permeability. This effect is bactericidal. Its use is indicated for infections caused by susceptible gram-negative bacteria, particularly Pseudomonas aeruginosa.

• Acute or chronic infections caused by susceptible gram-negative bacilli
• Enterobacter aerogenes infections
• Escherichia coli infections
• Klebsiella pneumoniae infections
• Pseudomonas aeruginosa infections

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.

Colistimethate alters bacterial cell membrane permeability, causing leakage of essential cellular components and bacterial cell death.

Adult Dose (Maintenance): 9 MIU/day in 2-3 divided doses. A loading dose of 9 MIU should be administered in critically ill patients.

Pediatric Dose (≤40 kg): 75,000-150,000 IU/kg/day divided into 3 doses.

Pediatric Dose (>40 kg): >150,000 IU/kg/day has been reported in children with cystic fibrosis.

Renal Dose:

Hemodialysis Patients: Non-HD days: 2.25 MIU/day; HD days: 3 MIU/day (after HD session).

IV Administration: Slowly inject one-half of the total daily dose over 3-5 minutes every 12 hours. Continuous Infusion: Administer the second half by slow IV infusion over 22-23 hours, starting 1-2 hours after the initial dose. Compatible with 0.9% NaCl, 5% dextrose solutions, Lactated Ringer's solution. Use reconstituted solution within 24 hours.

If you miss a dose of Colistimethate Sodium, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose. Do not double the dose.

Common Side Effects:

• Gastrointestinal upset
• Tingling of extremities and tongue
• Slurred speech
• Dizziness
• Vertigo
• Paresthesia
• Generalized itching
• Urticaria and rash
• Fever

Serious Side Effects:

• Increased BUN
• Elevated creatinine and decreased creatinine clearance
• Respiratory distress and apnea
• Nephrotoxicity
• Decreased urine output

• Use with caution in patients with impaired renal function; reduce dosage accordingly.
• Use with caution in neonates, infants and children.
• Avoid concurrent use with aminoglycosides and polymyxin (interfere with nerve transmission at neuromuscular junction).
• Avoid use with muscle relaxants (tubocurarine, ether, succinylcholine, gallamine, decamethonium, sodium citrate).

• Hypersensitivity to the drug or any of its components.

Avoid concurrent administration with aminoglycosides and polymyxin (interfere with nerve transmission at neuromuscular junction). Avoid use with muscle relaxants (tubocurarine, ether, succinylcholine, gallamine, decamethonium, sodium citrate). Avoid concomitant use with Sodium Cephalothin.

No food interactions have been found or established.

There are no adequate and well-controlled studies about the use of Colistimethate in pregnant women. Colistimethate is transferred across the placental barrier in humans. Should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

It is not known whether Colistimethate is excreted in human breast milk. Caution should be exercised when administered to nursing women.

Pediatric dose: ≤40 kg: 75,000-150,000 IU/kg/day in 3 divided doses; >40 kg: >150,000 IU/kg/day has been reported in cystic fibrosis. Use with caution in neonates, infants and children.

Limited information is available regarding dose adjustment for elderly patients.

[CAUTION] Use with caution in patients with kidney disease. Dose adjustment is necessary. Dose reductions are recommended for patients with creatinine clearance <50 ml/min.

There are no data in patients with hepatic impairment. Caution is advised.

Overdose symptoms: Paresthesia, lethargy, confusion, dizziness, ataxia, nystagmus, disorders of speech, apnea (respiratory muscle paralysis), acute renal failure (decreased urine output, increased BUN and creatinine). Treatment: Discontinue therapy and institute general supportive measures.

Before reconstitution: Store below 30°C. After reconstitution: Store at 2°C-8°C (Do not freeze) and use within 24 hours.

Colistimethate Sodium