808. Comparison of Serum Concentrations between Posaconazole Delayed-release Tablet and Oral Suspension at a Large Academic Medical Center
Session: Poster Abstract Session: Antimicrobial Agents: PK/PD Studies
Friday, October 9, 2015
Room: Poster Hall
Posters
  • Welch_ID Week Posa Poster.pdf (289.9 kB)
  • Background: Posaconazole (PCZ) is a broad spectrum azole antifungal with FDA approval for prophylaxis against invasive fungal infections (IFIs). Compared to the oral-suspension (OS), the delayed-release tablet (DRT) provides predictable absorption not reliant on intake with a high fat meal or an acidic environment. Off-label use of PCZ for treatment of IFIs is common and dosages of the OS are usually increased to 800 mg/day. No dosage recommendations have been made for treatment of IFIs with the DRT. We sought to evaluate differences between PCZ serum concentrations in patients receiving the DRT versus the OS and in patients receiving higher doses than 300 mg/day of the DRT. 

    Methods: A retrospective chart review was conducted on all inpatients that received PCZ for either treatment or prophylaxis from July 1, 2014 through December 31, 2014. Baseline demographics including comorbid conditions, indication, and dose of therapy were collected. Serum concentrations were considered appropriate if they were collected after at least 7 days of consecutive therapy. 

    Results: Fifty-seven patients received PCZ during the study period. The most frequent underlying medical conditions were bone-marrow transplant (35%), leukemia (28%), and solid organ transplantation (26%). Prophylaxis was the most common indication for use (61.4%). 22 patients received PCZ for treatment; organisms most commonly isolated included aspergillus (n=7), histoplasmosis (n=2), and mucormycosis (n=1). A total of 35 levels were collected during the study period (DRT n=18, OS n=17). The median daily dose was 300 mg for DRT and 600 mg for OS. Median serum concentrations (IQR) were significantly higher with the DRT [2.1 μg/mL (1.28-2.95)] vs. the OS [0.9 μg/mL (0.2-1.25)] (p<0.001). Patients receiving the DRT had levels within the therapeutic range (>0.7 μg/mL) 100% of the time compared to 58.8% in those receiving the OS. No difference was seen in serum concentrations at 300 mg/day (n=14) vs. 400 mg/day (n=8) of the DRT (1.55 μg/mL (1.08-2.5) vs. 2.5 μg/mL (1.85-2.7), p=0.19).

    Conclusion: The DRT leads to more consistent levels in the therapeutic range compared to the OS. Standard dosing of 300 mg/day of the DRT achieves adequate concentrations for prophylaxis and treatment.

    Sarah Welch, PharmD1, Andrea Pallotta, PharmD1, Catherine Weber, PharmD1, Caitlin Siebenaller, PharmD1, Eric Cober, MD2 and Elizabeth Neuner, PharmD1, (1)Pharmacy, Cleveland Clinic, Cleveland, OH, (2)Infectious Disease, Cleveland Clinic, Cleveland, OH

    Disclosures:

    S. Welch, None

    A. Pallotta, None

    C. Weber, None

    C. Siebenaller, None

    E. Cober, None

    E. Neuner, None

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