Relationship of Prolactin Concentrations to Steady-State Plasma Concentrations of Aripiprazole in Patients With Schizophrenia

Abstract

Background: Aripiprazole is regarded as the first-line antipsychotic medication. Long-term aripiprazole therapy can cause hypoprolactinemia, which may result from its activity as a dopamine agonist. However, there is little information on hypoprolactinemia and steady-state aripiprazole concentrations. Methods:The subjects included 66 male and 177 female patients diagnosed with schizophrenia who were treated with aripiprazole. The plasma concentrations of aripiprazole and dehydroaripiprazole and the plasma concentration of prolactin were measured using highperformance liquid chromatography and enzyme immunoassay, respectively. A prolactin concentration of ,5 ng/mL was defined as hypoprolactinemia.Results: Fifty-two of the 66 male patients (79%) and 58 of the 177 female patients (33%) had hypoprolactinemia. There were significant inverse correlations between plasma prolactin levels and plasma concentrations of aripiprazole (r s = 20.447, P , 0.001) and the active moiety (aripiprazole plus dehydroaripiprazole) (r s = 20.429, P , 0.001) in men. In women, significant inverse correlations were also found between plasma prolactin levels and plasma concentrations of aripiprazole (r s = 20.273, P , 0.01) and the active moiety (r s = 20.275, P , 0.01).Conclusions: These findings suggest that lower prolactin levels are, to some extent, associated with higher plasma drug concentrations in male and female patients with schizophrenia treated with aripiprazole.

Hypoprolactinemia and hyperprolactinemia in male schizophrenia patients treated with aripiprazole and risperidone and their relationships with testosterone levels

“…Therefore, the prolactin concentration can be controlled by the dose reduction of dopaminergic agents. These findings were in line with previous studies showing positive correlations between 9‐hydroxyrisperidone concentrations and prolactin 14 and inverse correlation between aripiprazole concentrations and prolactin, 15 and it may be natural that prolactin secretion is directly influenced by drug concentrations of dopaminergic agents because the pituitary gland is outside the blood‐brain barrier.…”