Extended dosing allows for high peak to MIC ratios potentially improving efficacy and reducing the risk of nephro- and ototoxicity. An extended-interval level drawn between 6-14 hours (after the start of the infusion) is recommended anytime after the first dose. Peak levels are not necessary and trough levels should be undetectable. Call pharmacy for assessment of aminoglycoside levels.
Target tobramycin levels: PEAK = 5-10 mg/L and TROUGH = < 1 mg/L. Peak levels should be drawn ½ hour following a ½ hour infusion. Trough levels should be obtained prior to the fourth dose of the regimen. Traditional dosing is the preferred method for Gram-positive synergy dosing in infective endocarditis. For patients with CrCl > 60 ml/min for whom synergy dosing is required, recommend 1 mg/kg/dose IV Q8h. Gram-positive synergy PEAK = 3-4 mcg/mL and TROUGH = undetectable.