It is not recommended by this committee for children because of lack of data, and it should be used with caution in people at increased risk for adverse events caused by aminoglycoside therapy, such as those with renal impairment or those taking other nephrotoxic drugs. In 1 study in adults,115 single daily doses of gentamicin (3 mg/kg per day) combined with cef- triaxone (2 g/d for adults) for 2 weeks were as effective as 4 weeks of ceftriaxone alone. Although once-daily dosing of gentamicin has become an accepted practice for adult patients with infections other than endocarditis, few studies detail- ing the use of this regimen for the treatment of streptococcal endocarditis in adults have been published. Several stud- ies have demonstrated the safety and efficacy of once-daily dosing of gentamicin in children with infections other than endocarditis; however, no studies describing outcomes after the use of single daily dosing of gentamicin for the treatment of IE in children have been published. Occasionally, IE may be caused by streptococci that are relatively resistant to penicillin (MIC between 0.1 and 0.5 g/ mL). In this situation, concern about the efficacy of penicillin alone is avoided by use of a treatment regimen of 4 weeks of penicillin, ampicillin, or ceftriaxone combined with gentamicin for the first 2 weeks. Patients with IE caused by Abiotrophia, Granulicatella species, or streptococci with an MIC of >0.5 g of penicillin per milliliter should be treated with the antibiotic regimen listed for enterococci. For children who are unable to tolerate -lactam antibiotic drugs, vancomycin is an effective substitute, and current practice includes the addition of genta- micin for a 4-week course (Table 7). 