Aminoglycosides Flashcards
Aminoglycosides MOA
Crosses outer bacterial membrane by passive diffusion via porin channels, then binds to 30s ribosomal subunit and thus inhibits protein synthesis
(Bactericidal)
Mechanism of resistance
Transferase enzyme inactivates aminoglycoside (main mechanism)
Impaired entry of aminoglycoside into the cell (genotypic or phenotypic)
Receptor protein on 30S ribosomal subunit may be deleted or altered
Gentamicin (Garamycin)
Most widely used
Effective for both gram-negatives and gram-positive (although resistance occurs)
Almost always used in combination with another antibiotic (beta-lactam)
IV, IM
Topical
Ophthalmic (eye drop)
Tobramycin (Nebcin)
Similar coverage overall to gentamicin, except better Pseudomonas coverage
More expensive than gentamicin
Also comes as a solution for inhalation for cystic fibrosis
IV, IM
Ophthalmic
Amikacin (Amikin)
Used for resistant bacteria
IV, IM
Streptomycin
2nd line for tuberculosis in combination with other agents
Used in combination with penicillin or ampicillin for Enterococcus faecalis endocarditis or Viridans streptococcus endocarditis, although some resistance has emerged
IM
Neomycin (Mycifradin)
Limited to topical and oral use (bowel prep for surgery with erythromycin)
Resistance exists especially to Pseudomonas and Streptococci
Paromomycin (Humatin)
For intestinal amebiasis And hepatic coma/encephalopathy
Oral
AminoglycosidesUse during pregnancy and breastfeeding
Pregnancy Category: D (there is evidence of human risk, but clinical benefits may outweigh risk)
they are considered compatible with use during breastfeeding
AminoglycosidesContraindications
Previous allergy or hypersensitivity reaction to aminoglycosides
Myasthenia gravis- neuromuscular blockade risk too high
BLACK BOX WARNINGS
NEPHROTOXICITY- reversible
OTOTOXICITY- vestibular and cochlear
NEUROTOXICITY
NEUROMUSCULAR BLOCKADE
