Low-dose risperidone augmentation of antidepressants or anxiolytics is associated with hyperprolactinemia

Risperidone in antipsychotic doses induces hyperprolactinemia. The aim of this study was to verify whether the same is true for low doses of risperidone (0.5-2 mg per day) added to antidepressants or anxiolytics.

Prolactin levels were measured in 4 men (mean age 49.5+/-19.1 years) and 8 women (mean age 31.3+/-8.2 years) inpatients with depressive and anxiety disorders who were treated with risperidone (median doses per day 1.25 mg) for median 15.5 days as an augmentation treatment to antidepressants (n=8), anxiolytics (n=6) and mood stabilizers (n=2).

11 of 12 patients had hyperprolactinemia. Median plasma prolactin level was 1598 mIU/ml, 95% CI 1 040-2 661 mIU/ml. Significant correlation between risperidone daily dose and plasma prolactin level (Spearman's R=0.655, p=0.02) was detected. Two women suffered from galactorrhea and one from amenorrhea.

Even low doses of risperidone used as an augmentation to antidepressants or benzodiazepines are associated with hyperprolactinemia and can induce endocrinological side effects. The co-medication of antidepressants and benzodiazepines can potentially increase intensity of prolactinemia.