Bankground: A second-generation triazole, posaconazole, has been used for prophylaxis and treatment for fungal infections in high risk individuals. However, efficacy of posaconazole has never been evaluated in Thai patients which have higher prevalence of invasive fungal diseases. 
Objective: The objective of this study is to evaluate the efficacy of posaconazole oral suspension in prevention and treatment of invasive fungal diseases in a tertiary care hospital in Thailand.
Methods: We retrospectively reviewed medical records of patients admitted at Siriraj Hospital, who were prescribed posaconazole for either prophylaxis or treatment, from January 2010 to December 2016. Clinical characteristics, breakthrough infections and treatment outcomes were analyzed.
Results: There were 80 patients enrolled in this study. A total of 71 patients received posaconazole for prophylaxis and all of them had hematologic malignancies with neutropenia. Among 9 patients who received posaconazole for treatment of invasive fungal diseases, 4 had diabetes mellitus and the other 4 had hematologic malignancies. In those who received prophylaxis, breakthrough invasive fungal diseases were found in 13 patients (18.3%) and invasive aspergillosis was the most common infection (9 patients, 69%). The median time to performed posaconazole therapeutic drug concentration in those with and without breakthrough infections were 7 and 13 days, respectively (p = 0.029). Approximately 50% of patients with breakthrough fungal infections had suboptimal plasma posaconazole concentration (< 0.7 µg/ml), whereas suboptimal concentration was found in only 29% in those without breakthrough infection (p = 0.169). In treatment group, 8 patients (88.9%) were cured. One patient died and she was the only one who had hematologic malignancy and did not perform therapeutic drug monitoring.
Conclusions: Posaconazole oral suspension seem to be less efficacious in preventing IFD in Thai, partly may be due to higher incidence of invasive fungal diseases, lack or delayed therapeutic drug monitoring resulting in suboptimal plasma drug concentration. Posaconazole was effective in treatment of IFD.

Efficacy of Posaconazole Oral Suspension in Prevention and Treatment of Invasive Fungal Infections in A Tertiary Care Hospital in Thailand