Measure serum trough concentrations at least weekly. Serum trough levels of at least 15 mg/L recommended for most gram-positive infections; 30-40 mg/L recommended for endocarditis or more severe infections.
Obtain cultures and WBC count.
Monitor CBC, renal and hepatic functions, and hematologic parameters.
Perform auditory testing in patients with renal insufficiency or those receiving concomitant nephrotoxic or ototoxic medications.