Vancomycin
is a glycopeptide antibiotic mainly indicated against gram positive cocci,
specially meticillin-resistant-S. Aureus and ampicillin-resistant-Enterococcus.
Because of the
variability of serum vancomycin levels, the risk of toxicity and the different
commercial vancomycin sources, we carried out a prospective study to evaluate
peak and trough level of vancomycin. Thirty patients with severe undelying diseases and
infections were included; 16(53%) females and 14(47%) males, mean age (SD)
5.7(4.8), range 1month-17 years. Patients were given 40 mg/kg daily in four
diveded dosis and 60 mg/kg daily (same schedule) when they suffered from
central nervous system infections (CNS). Two samples were drawn at peak (one
hour post-infusion) and trough (just before next dose) time. Sawchuck-Saske
method was used to fit data and obtain
pharmacokinetic
parameters. Target peak concentration was 20-40 mg/l and the desired trough
concentration was between 5-15 mg/l. Serum concentration values were
inappropriated in 17(57 %) patients:
peak and trough 10(33 %), peak only 5(17 %), trough only 2(7 %). Malignancies
were present in 5/10 patients of the peak and trough unsuitable concentration
group (4 were neutropenic). Drug concentration was evaluated after changing the
dosage in 9 patients; eight of them achieved the expected values.
The
results could be mainly related to the underlying disease; another factor could
be the different origins of the vancomycin. Our data suggests the need for
routine vancomycin monitoring. This practice is highly recommended in patients
suffering infections with risk of death and/or infections with CNS compromise.