raw material Polymyxin B sulfate

Polymyxin B sulfate More Info

Polymyxin B sulfate is a polypeptide antibiotic primarily used to treat severe infections caused by sensitive Gram-negative bacteria. It is especially effective against multidrug-resistant (MDR) strains that are unresponsive to other antibiotics.

1. Core Indications

Its clinical use focuses on life-threatening or difficult-to-treat infections, mainly including:

Bloodstream infections: Such as sepsis caused by sensitive Gram-negative bacteria (e.g., Pseudomonas aeruginosa).

Urinary tract infections (UTIs): Used when common antibiotics (e.g., cephalosporins, quinolones) fail.

Skin and soft tissue infections: For local or systemic treatment of infections caused by sensitive strains.

Meningitis: Administered intrathecally (into the spinal canal) in rare cases to treat Gram-negative bacterial meningitis that is unresponsive to other therapies.

2. Mechanism of Action

It exerts antibacterial effects by disrupting the structure and function of bacterial cell membranes:

It binds to lipopolysaccharides (LPS) on the outer membrane of Gram-negative bacteria.

This binding destroys the integrity of the bacterial outer membrane, causing leakage of intracellular components (e.g., electrolytes, proteins).

The leakage of essential substances leads to bacterial death, making it a bactericidal antibiotic (directly kills bacteria, rather than inhibiting growth).

3. Administration Routes

The route is determined by the type and severity of the infection:

Intravenous (IV) injection: The main route for systemic infections (e.g., sepsis, severe UTIs).

Intramuscular (IM) injection: Used for milder systemic infections or when IV administration is not feasible.

Topical application: Available as ointments or eye drops for local infections (e.g., skin wounds, bacterial conjunctivitis).

Intrathecal/intraventricular injection: A specialized route for central nervous system (CNS) infections (e.g., meningitis), requiring strict medical supervision.

4. Key Safety Information

It has a narrow therapeutic window, so potential adverse effects must be closely monitored:

Nephrotoxicity (kidney damage): The most common serious adverse effect, which may manifest as increased serum creatinine or decreased urine output. Renal function must be checked regularly during treatment.

Neurotoxicity: May cause symptoms such as dizziness, numbness (around the mouth or extremities), confusion, or even neuromuscular paralysis (rare, but more likely with high doses or concurrent use of muscle relaxants).

Allergic reactions: Can range from mild rashes to severe anaphylaxis. Use with caution in patients with a history of allergies to polypeptide antibiotics.

Drug interactions: Avoid concurrent use with other nephrotoxic drugs (e.g., aminoglycosides like gentamicin, non-steroidal anti-inflammatory drugs/NSAIDs) to reduce the risk of kidney damage.

5. Precautions for Use

It is a last-resort antibiotic and is generally used only when other safer antibiotics are ineffective or contraindicated, to slow the development of bacterial resistance.

Dosage must be adjusted based on renal function, especially in elderly patients or those with pre-existing kidney disease.

During treatment, monitor not only renal function but also electrolyte levels (e.g., potassium, magnesium) to prevent imbalances.