Macrolide Antibiotics and Gentamicin: Mechanism, Uses, and Side Effects Explained

Macrolide Antibiotics and Gentamicin: Mechanism, Uses, and Side Effects Explained

Question 1. Write A Short Note On Macrolide Antibiotics.
Answer:

These are the antibiotics having a macrocyclic lactone ring with the attached sugars.

• These include erythromycin, clarithromycin roxithromycin, and azithromycin which are bacteriostatic in low concentrations and bactericidal in large concentrations.
• They inhibit protein synthesis by binding to 50 S ribosomal RNA.
• Antibiotics are used against Gram-positive organisms.

Macrolide Antibiotics: Uses, Mechanism, and Side Effects

Question 2. Write A Short Note On Gentamicin.
Answer:

It is a systemic aminoglycoside.

Gentamicin Mechanism Of Action

It is a bactericidal antibiotic. Its action is as follows:

• There is transport of aminoglycoside through the bacterial cell wall and cytoplasmic cell membrane.
• Binding to ribosomes result in the inhibition of protein synthesis.

Gentamicin Antibacterial Spectrum

• Gentamicin is used for gram-negative infections caused by E. coli, Klebsiella, Proteus, and Pseudomonas aeruginosa. The drug is also effective against Gram-positive infections caused by enterococci, streptococci, and staphylococci.
• Gentamicin also inhibits Streptococcus fecalis and various Staphylococcus aureus.

Macrolide Antibiotics and Gentamicin: Mechanism of Action and Side Effects

Uses Of Gentamicin

• Gentamicin is used in subacute bacterial endocarditis along with penicillin.
• It can be used alone or in combination with penicillin or cephalosporins in critically ill patients to prevent respiratory infections, in postoperative pneumonia. In patients with implants, community-acquired pneumonia.
• It can be used in burns, UTIs, pneumonia, lung abscess, osteomyelitis, septicemia, and middle ear infections.
• In infections caused by Gram-negative bacilli, i.e. urinary tract infections with pyelonephritis, pneumonia, meningitis, osteomyelitis, septicemia, and infected burns.
• In dentistry, gentamicin is used in combination with amoxicillin for prophylaxis of endocarditis in high-risk patients before the commencement of the dental procedure.
• Topically gentamicin is used as an ointment for skin lesions and burns. It is also used as an eye drop in conjunctivitis.

Adverse Effects Of Gentamicin

• Nephrotoxicity: It is encountered when therapy is continued for several days or in renal insufficiency, but this is reversible. Gentamicin binds to phospholipids of the renal brush border and leads to renal necrosis.
• Ototoxicity: When gentamicin gets concentrated in endolymph it leads to vestibular toxicity, i.e. vertigo and ataxia. The drug also gets concentrated in the perilymph of the inner ear and leads to cochlear toxicity, i.e. tinnitus and
  hearing loss.
• Neuromuscular blockade: Gentamicin blocks neuromuscular receptors of the motor endplate and leads to neuromuscular blockade.