Name: Tobramycin (Nebcin)
Class: Aminoglycoside
Mech.: O2 dependent uptake ® inhib. of protein synth by binding to 30S rib. subunit ® leaky membranes. Bactericidal.
Absorption: Poor oral absorption. Usu. IM or IV.
Distribution: Limited to extracellular space. Poor CSF, ocular. No placenta.
Excretion, t½: glomerular filtration. 2 hrs.
Toxicity/S.E.s: Ototoxicity (aud., vest.), nephtrotoxicity (less than gentamicin).
Utility: Nosocomial aerobic gram- infects, esp. in immunocomp, neutropenics. Often used in synergistic combs to treat P. aeruginosa, enteroccus, life-threatening gram- sepsis. Used in comb. against S. aureus. Ineffective against anaerobes.
Special Features: Resistance 1° due to plasmid-med. mod. of aminoglyc. Also alter. of transport system, mutation of rib. subunit.