Clinical Drug Experience Knowledgebase

Sisomicin is a new broad-spectrum aminoglycoside most closely related structurally to gentamicin C1a. In vitro and in experimental infections, sisomicin has been found to be more potent than or nearly as potent as the most active of the other available aminoglycosides. Although susceptible to many (but not all) aminoglycoside-inactivating enzymes, sisomicin is active against many microorganisms that are resistant to other aminoglycosides by nonenzymatic mechanisms. Sisomicin has been shown to interact synergistically with various beta-lactam antibiotics against enterococci, staphylocicci, Enterobacteriaceae, and nonfermentative gram-negative bacilli. The pharmacokinetics and toxicity of sisomicin in humans appear to be similar to those of gentamicin, despite earlier reports of greater acute toxicity in animals. Sisomicin binds to 30s and 50s ribosomal subunits of susceptible bacteria disrupting protein synthesis, thus rendering the bacterial cell membrane defective.   ^NCATS