Evaluation of serum prolactin levels in intellectually disabled patients using antipsychotic medications

Patients with intellectual disabilities may be treated with antipsychotic medications for a variety of diagnoses. Use of this category of medication can increase prolactin levels and place the patient at risk for sexual dysfunction and lower bone mineral density. The proposed mechanism of action is affinity for the dopamine receptor. Use of bromocriptine, a dopamine receptor antagonist, was proposed to attenuate hyperprolactinemia.

The objectives of this study were to (1) review serum prolactin (PRL) elevations associated with the use of antipsychotic (AP) medications in an intellectually disabled adult population and (2) determine if any association existed between the level of elevation and AP used.

Medical records for adult patients at two Oklahoma facilities for the intellectually disabled were reviewed to evaluate prolactin levels for individuals prescribed antipsychotics. A linear regression model was used to evaluate the relationship between prolactin levels with intellectual disability level, bromocriptine use, demographics, and antipsychotic.

73 (n = 53 males, n = 20 females) patients met criteria. The average age was 41.2 years. Nearly 70% of the patients had severe to profound levels of disability. 77% were prescribed second generation antipsychotics; 19% received first generation agents. Two variables, gender and bromocriptine use, were found to be significant predictors of prolactin levels. Mean prolactin level for females was 44 ng/mL (normal range: 4-30 ng/mL, males = 4-23 ng/mL). Patients who did not receive bromocriptine had mean levels of 23 ng/mL. No significant difference in prolactin levels was found for type of AP.

Mean prolactin levels for females were significantly higher than for males. Both sexes were found to have higher-than-normal levels. Use of bromocriptine was associated with higher prolactin levels. In this population of patients, the type of AP used had no significance on prolactin levels.