Aminoglycosides continue to fulfill a key role in the treatment of severe gram-negative infections despite the availability of newer antibacterial agents that are associated with less risk of nephrotoxicity or ototoxicity. When compared with gentamicin, tobramycin has a similar spectrum of activity against gram-negative bacteria but higher activity against Pseudomonas species and is less likely to cause nephrotoxicity. Consequently, tobramycin is the aminoglycoside of choice for the treatment of confirmed Pseudomonas species infections and mixed infections, including Pseudomonas aeruginosa with other organisms. Tobramycin is similarly preferred for the initial, emergency treatment of patients who have, or are at risk of developing, severe P aeruginosa-related infections (eg, patients with neutropenia, burns, or cystic fibrosis). Selection of a dosing regimen is an important consideration before implementing treatment. Historically, in the absence of specific pharmacologic data for the aminoglycosides, multiple-daily dosing (MDD) schedules, extrapolated from experience with other antibiotics, have been used to deliver aminoglycosides. However, recent pharmacodynamic data for the aminoglycosides have supported the concept of once-daily dosing (ODD). Clinical investigations comparing ODD with traditional MDD, typically in immunocompetent adult patients who have normal renal function, suggest that ODD is as effective as and no more toxic than traditional MDD. These features, combined with the likelihood of direct health care cost savings, suggest that ODD may be preferable to MDD in some patient groups. However, the effect of ODD has not been investigated extensively in children or in pregnant, immunocompressed, renally insufficient, or critically ill patients, and application of the regimen in these special patient populations cannot be recommended until data become available.
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