Voriconazole therapeutic drug monitoring practices in the intensive care

BACKGROUND: Routine therapeutic drug monitoring of voriconazole appears to be beneficial. This study investigated the therapeutic drug monitoring practices in intensive care to derive possible recommendations for improvement.METHODS: A retrospective chart review was performed for patients aged ≥ 18 years that started treatment with voriconazole which lasted for at least three days while admitted to an intensive care unit (ICU) to assess possible differences between the patients with and without voriconazole trough concentrations measured.RESULTS: In 64 (76%) of the 84 patients, voriconazole trough concentrations were measured. The groups differed significantly with respect to the duration of voriconazole treatment and ICU admission. Time of sampling was to early and therefore inappropriate for 49% of the first measured voriconazole trough concentrations and in 48% of the subsequent measured concentrations. Of the 349 trough concentrations measured, 129 (37%) were outside the therapeutic window. In 11% of these cases no recommendation was provided without identifiable reason. In addition, 27% of recommended dose adjustments were not implemented, probably because the advice was not suited for the specific clinical situation.CONCLUSION: The performance of voriconazole therapeutic drug monitoring can still be improved although voriconazole concentrations were monitored in most patients. A multidisciplinary approach - for instance by means of antifungal stewardship will probably be able to overcome problems encountered like timing of sampling, incompleteness of data on clinical context and lack of implementation of recommendations.