Comparison of prolactin concentrations between haloperidol and risperidone treatments in the same female patients with schizophrenia

Abstract

The present study aimed to investigate intraindividual changes in plasma prolactin concentrations by switching from haloperidol treatment to risperidone treatment. The subjects were 15 female schizophrenic inpatients who received firstly haloperidol 12 mg/day for at least 2 weeks and, thereafter, risperidone 6 mg/day. Prolactin concentration in plasma during risperidone treatment (median 87.5 ng/ml, range 5.3-298.1 ng/ml) was significantly ( P<0.01) higher than during haloperidol treatment (median 50.7 ng/ml, range 11.6-226.6 ng/ml). In contrast, the ratio of prolactin concentration to nmol/l unit drug concentration (the active moiety: the sum of risperidone and 9-hydroxyrisperidone) during risperidone treatment (median 1.10, range 0.02-3.73) was significantly lower ( P<0.001) than that of haloperidol (median 1.81, range 0.41-8.24). Prolactin concentrations during both treatment phases correlated well in individuals (r=0.619, P<0.05), whereas better correlation was found in the ratio of prolactin concentration to drug concentration (r=0.779, P<0.01). These findings suggest the higher risk of hyperprolactinemia during risperidone treatment than during haloperidol treatment at clinically used dosages. However, from a purely pharmacological point of view, prolactin response per drug concentration was more sensitive during haloperidol treatment than risperidone treatment, probably resulting from the potent and selective antagonistic effect of haloperidol on dopamine D(2) receptor, compared with the broader pharmacological spectrum of risperidone.

Effect of age and disease on bone mass in Japanese patients with schizophrenia

“…However, most antipsychotics block dopamine-D2 receptors, attenuating the inhibitory effect of dopamine on prolactin release from the pituitary gland and resulting in hyperprolactinemia [28]. Previous studies have shown that patients who are treated with antipsychotics have elevated prolactin levels [6,29], which is correlated with decreased bone mass in schizophrenic patients. Even when a direct effect of prolactin on BMD was not observed, the duration of antipsychotic treatment had a tendency to be associated with decreased BMD [30], and patients with hyperprolactinemia showed higher rates of bone metabolism, including both bone formation and resorption [5].…”

Prolactin levels in male schizophrenic patients treated with risperidone and haloperidol: a double-blind and randomized study

“…Recently, however, risperidone, an atypical antipsychotic has been reported to be implicated in a significant increase in PRL (Breier et al 1999;Kleinberg et al 1999;David et al 2000;Markianos et al 2001;Zhang et al 2002;YasuiFurukori et al 2002;Kaneda and Ohmori 2003). Moreover, a recent study investigated intraindividual changes in plasma PRL concentrations by switching from haloperidol treatment to risperidone treatment, showing higher risk of hyperprolactinemia during risperidone treatment than during haloperidol treatment (Yasui-Furukori et al 2002). To date, however, the mechanism by which risperidone treatment results in elevated PRL levels is still not clear.…”

No association between bone mass and prolactin levels among patients with schizophrenia

“…Most antipsychotics block dopamine‐2 receptors; thus, the inhibitory effect of dopamine on prolactin release from the pituitary gland is attenuated, resulting in hyperprolactinemia (Haddad and Wieck, ). Some studies have shown that patients who are treated with antipsychotics have elevated prolactin levels (Yasui‐Furukori et al , ; Meaney et al , ). People taking antipsychotic medications have also been shown to be at risk for osteoporosis (Howard et al , ).…”