GENTAMICIN

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Gentamicin is an aminoglycoside antibiotic that is not directly involved in the process of anesthesia but plays a crucial role in the perioperative period for preventing and managing infections related to surgical procedures. The importance of gentamicin in the context of anesthesia can be highlighted by the following factors:

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1. Surgical prophylaxis: Gentamicin is used as a prophylactic antibiotic for surgeries where there is a risk of bacterial contamination, particularly when gram-negative bacteria are suspected. It is often administered as a single dose before surgery and may be combined with other antibiotics, such as a beta-lactam or vancomycin, to provide broader coverage against potential pathogens. Proper timing and dosing are essential to ensure adequate tissue concentration during surgery.

2. Treatment of infections: Gentamicin may be used to treat established infections in the perioperative period, such as wound infections, sepsis, or pneumonia. The choice of gentamicin as a treatment option depends on the suspected or confirmed causative organisms and their susceptibility patterns.

3. Gram-negative coverage: Gentamicin is particularly effective against gram-negative bacteria, making it a valuable option for surgical prophylaxis and treatment in situations where gram-negative pathogens are of concern.

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The mechanism of action of gentamicin can be summarized as follows:

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1. Entry into bacterial cells: Gentamicin penetrates the bacterial cell wall and cytoplasmic membrane through an energy-dependent, active transport process. The initial binding of gentamicin to the bacterial cell surface is facilitated by its interaction with specific receptors on the outer membrane of gram-negative bacteria.

2. Binding to ribosomes: Once inside the bacterial cell, gentamicin binds to the 30S subunit of bacterial ribosomes. This binding interferes with the normal function of the ribosome, which is essential for bacterial protein synthesis.

3. Inhibition of protein synthesis: By binding to the 30S ribosomal subunit, gentamicin causes misreading of the genetic code and prevents the formation of a proper initiation complex. This leads to the incorporation of incorrect amino acids into the growing polypeptide chain, which results in the production of nonfunctional or toxic proteins.

4. Bactericidal effect: The overall effect of gentamicin's action on bacterial protein synthesis is bactericidal, meaning it kills the bacteria rather than just inhibiting their growth. By interfering with protein synthesis, gentamicin causes the production of aberrant proteins that can be toxic to the bacterial cell, leading to cell death.

5. Disruption of bacterial cell membrane: In addition to its primary action on protein synthesis, gentamicin may also cause disruption of the bacterial cell membrane by interacting with membrane phospholipids. This disruption further contributes to the bactericidal effect of the antibiotic.

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                                                                                         Key points about Gentamicin

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• Inhibits protein synthesis in bacteria at level of 30S ribosome.

 

• Aminoglycosides are rapidly bactericidal for aerobic gram-negative bacteria.

 

• Gentamicin is active against P. aeruginosa as well as the gram-negative bacilli.

 

• The side effects of aminoglycosides that limit their clinical usefulness include ototoxicity, nephrotoxicity, skeletal muscle weakness, and potentiation of nondepolarizing neuromuscular blocking drugs.

 

• Aminoglycosides have the ability to inhibit the prejunctional release of acetylcholine.

 

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