General structure and mechanism of Aminoglycosides

amino sugars attach in glycosidic links to aminocyclitol ring.

Polycations (veyr polar)

Usually given IV, some oral to clean out bowel

Mechanism: goes into periplasmic space og G- through porin channels. Flow down electrochemical gradient and inhibit initiation, misreading of DNA (faulty proteins), premature termination (breaks up polysomes)

Are cidal (dont know why)

Not effective vs anaerobes because there is no electrochemical gradient

Highest level in renal cortex (nephrotoxic, reversible) and endolymph (ototoxic, irreversible)

IV

topical cream/ointment for burns, wounds, and to prevent catheter infections.

opthalmic for ocular infections

IV

Generally interchangeable with gentamcin. Posisbly less ototoxic

Amikacin (generic) 

IV

Enzyme resistant.  For nosocomial infections that resist gentamicin & tobramycin.

Oral

oral to prep for bowel surgery, topical antiinfectant

neuromuscular block (respiratory paralysis) by:

1) blocking Ca uptake (decrease ACh release)

2) block postsynaptic ACh receptor

treat with IV Ca

can use neostigmine instead (ACh Esterase Inhibitor)

Dont give to pts with myasthenia gravis