Abstract
Background
Dose-related reference ranges can be used in therapeutic drug monitoring to
monitor pharmacotherapy. The deviation of a measured serum concentration
from the expected serum concentration at the corresponding dose can thus be
identified early and responded to appropriately. The serum concentrations of
patients treated with cariprazine regularly deviated from this dose-related
reference range. As this is a relatively new drug with only one
recommendation on values for a dose-related reference range, the values were
tested for validity using real-world data.
Methods
Serum concentrations of 24 patients receiving cariprazine once daily were
analyzed retrospectively. Only patients without pharmacokinetic
abnormalities were included. The measured serum concentrations were compared
with the values of the dose-related reference range in the guidelines of the
Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie
consensus guidelines of 2017 and checked whether a sufficient number of
serum concentrations were within the dose-related reference range.
Results
Only 45.8% of the measured serum concentrations were within the dose-related
reference range. The C/D ratio was 1.58±0.73. Accordingly, a lower value of
0.85 and an upper value of 2.31 were calculated for the updated dose-related
reference range, which is below the currently recommended values.
Conclusion
The results suggest that the current values for the dose-related reference
range are too high and require adjustment. The updated dose-related
reference range lies between 0.85 and 2.31, with a mean of 1.58±0.73.
Keywords
cariprazine - dose-related reference range - therapeutic drug monitoring - AGNP consensus
guidelines
