Prolactin levels in young children with pervasive developmental disorders during risperidone treatment.

Although hyperprolactinemia is a common side effect during risperidone treatment in adult patients, no information is available on young children. The aim of this study is to report on serum prolactin levels in 25 young autistic children (22 males and 3 females, age range 3.9-7 years, mean age 4.10 years) during treatment with risperidone (dosage range 0.25-0.90 mg/day, mean dosage 0.52 mg/day). Prolactin levels were measured at baseline and after 10 weeks of treatment. The clinical outcome measure used was the Clinical Global Impression-Improvement. Serum prolactin was 9.77 +/- 3.94 ng/mL at baseline and 25.92 +/- 13.9 ng/mL during the 10th week of treatment (p < 0.001). Six children (24%) showed prolactin levels lower than 15 ng/mL, which is the upper normal level; eight children (28%) had prolactin levels higher than two times the upper limit (30 ng/mL). Hyperprolactinemia did not show significant correlations with age, weight, or risperidone dosage. There was no relation with clinical outcome. Dose reduction of risperidone resulted in a decrease of prolactin levels. None of the children showed clinical signs of hyperprolactinemia. Given the paucity of available data on potential effects of long-term hyperprolactinemia, a monitoring of prolactin during treatment with risperidone and other typical and atypical antipsychotics may be warranted.