Background Optimising glycopeptide and aminoglycoside treatment with Therapeutic Drug Monitoring is recommended. Under-dosing can lead to resistance and ineffective treatment while over-dosing is associated with toxicity.

Purpose To evaluate current practise by monitoring aminoglycosides and glycopeptides in a French university hospital: levels (trough and peak concentrations) and percentage of optimal concentrations based on our internal antibiotics guide.

Materials and Methods Prescriptions for glycopeptides and/or aminoglycosides, of which at least one dose had been given, were reviewed over one month (February–March 2012). Our data pool contained: patient characteristics, infection and antibiotic treatment background, serum concentration.

Results A wide range of official optimal target serum concentrations has been recommended (Consensus Review of the American Society of Health-System Pharmacists, French Pharmacology and Therapeutic Society, internal guidelines, etc.)

91 prescriptions (31 aminoglycosides, 60 glycopeptides) were analysed: the largest percentage was represented by vancomycin (55%) 80% of which were for continuous infusion. Serum vancomycin concentrations are optimised by using continuous regimens (Table 1).

For the two regimens, (continuous and intermittent, 10% of trough vancomycin serum concentrations were below 10 mg/L, exposing the patient to to subtherapeutic doses and a higher risk of selecting resistant microorganisms.

10 prescriptions for teicoplanin were reviewed: 70% of serum concentrations were below 20 mg/L and 30% below 10 mg/L.

50% of aminoglycosides trough concentrations were below the internal guideline values and target peak concentrations were not reached (amikacin: 67% under 60 mg/L, gentamycin: 90% under 30 mg/L).

Conclusions Most aminoglycosides and glycopeptides concentrations didn’t reach required therapeutic levels during this study. Consensus guidelines should be proposed to avoid bacterial resistance and guide clinical practise.

No conflict of interest.