MAJORITY OF PATIENTS DOES NOT ACHIEVE THERAPEUTIC TROUGH LEVELS FOLLOWING A FIXED DOSE VANCOMYCIN ADMINISTRATION: EXPERIENCE FROM SOUTH INDIA

Abstract

Intro: Vancomycin trough-guided dosing has been recommended to optimize the dose to improve efficacy and to prevent adverse effects like nephrotoxicity. Most hospitals in India use a standard dosing of Vancomycin (1 g every 12th hourly) and therapeutic drug monitoring facilities are not available. We studied vancomycin trough levels in patients admitted to a tertiary care hospital in South India. Methods: Clinical details of patients with normal renal function, who received Vancomycin over a 1-year period were collected from the electronic medical records. Vancomycin trough levels were done in all patients receiving Vancomycin just before the fourth dose. Findings: 70 patients were included in the study. Only 18.5% had a vancomycin trough level concentration between 15 mg/L and 20 mg/L (therapeutic levels). 71.4% had a trough level less than 15 mg/L (subtherapeutic level), while 10 % had trough concentration more than 20 mg/L. Height and weight were significantly different between the three groups. Post-hoc Mann-Whitney test showed that patients who had sub-therapeutic levels had significantly higher weight (p=0.033) and height (p=0.024) when compared to supratherapeutic levels. The body mass index was however not significantly different between the groups. Both height (r = -0.275, p = 0.021) and weight (r = -0.244, p = 0.042) had statistically significant negative correlation with vancomycin trough levels. Conclusion: Majority of the patients did not achieve a therapeutic trough level following administration of a fixed dose of Vancomycin. Patients with subtherapeutic levels had significantly higher weight and height compared to those who achieved a therapeutic level.