AMINOGLYCOSIDES ANTIBIOTICS...
EXAMPLES: Gentamicin, tobramycin, amikacin, neomycin, streptomycin.
MECHANISM OF ACTION: Bacteriocidal antibiotic that blocks protein synthesis by binding to
the bacterial 30S ribosomal subunit. This prevents the process of tRNA attachment and mRNA
translation is disrupted.
- Septicaemia
- Biliary tract infection
- Acute pyelonephritis and prostatitis
- Endocarditis
- Adjunct in Listeria meningitis
- Myasthenia gravis (aminoglycosides can impair neurotransmission within muscles).
- Caution in renal failure (doses should be reduced).
- GI disturbance.
- Nephrotoxicity.
- Rash and vestibular and auditory damage (ototoxicity).
- Blood dyscrasias.
- Aminoglycosides are excreted unchanged in the urine.
- t½ for gentamicin is 2–3 h.
- Regular monitoring of U&Es.
- For single daily dosing, gentamicin level must be taken 6–12 h after the first dose.
- Levels should be interpreted using the Hartford Nomogram, which will determine dosing frequency.
- Increased risk of ototoxicity with loop diuretics.
- Aminoglycosides can enhance the effects of non-depolarising muscle relaxants.
- Increased risk of nephrotoxicity with ciclosporin.
- Predominantly Gram-negative Enterobacteria spp. cover (e.g. UTI, abdominal sepsis) and Pseudomonas spp.
- Poor oral absorption hence given parenterally (except neomycin).
- Once daily aminoglycoside dosing is preferable and provides adequate serum concentrations. Exceptions include the treatment of bacterial endocarditis.
- Continuation of gentamicin therapy for more than 7 days carries an increased risk of nephrotoxicity and ototoxicity.
