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Smoking prevalence for schizophrenic patients is higher than for the general population. Inter-individual variability in hyperprolactinemia induced antipsychotics particularly risperidone can be explained by smoking status to some extent. We therefore studied the effects of smoking status on the plasma concentration of prolactin. Subjects included 154 schizophrenia patients (61 males, 93 females) who had received 3 mg of risperidone twice daily for at least 4 weeks. Sample collections were conducted 12 h after the bedtime dosing. The plasma concentrations of prolactin in the females were significantly higher than in the males (117.6±69.3 ng/ml vs. 52.9±30.7 ng/ml, p<0.001). The mean (±SD) plasma concentrations of prolactin did not differ between smokers and nonsmokers in the males (59.5±31.2 ng/ml vs. 47.6±29.3 ng/ml, not significant (ns)), but there was a significant difference in the females (100.2±59.1 vs. 134.0±74.6, ng/ml, p<0.05). Multiple regression analyses including gender, plasma drug concentration and age revealed that the plasma concentration of prolactin positively correlated with gender (standardized beta=0.452, p<0.001) and negatively with age (standardized beta=-0.171, p<0.05) and smoking status (standardized beta=-0.232, p<0.01). These findings suggest that smoking status has an impact on prolactin concentration during risperidone treatment. However, further study is required to determine whether these findings have clinical implications., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Hyperprolactinemia is a frequent consequence of treatment with risperidone. Recent studies have suggested that aripiprazole, a partial dopamine agonist, reduces the prolactin response to antipsychotics. Thus, we examined the dose effects of adjunctive treatment with aripiprazole on the plasma concentration of prolactin in patients who had elevated prolactin levels because of risperidone treatment. Aripiprazole was concomitantly administrated to 16 female patients with schizophrenia receiving 2 to 15 mg/d of risperidone. Dosages of aripiprazole were gradually increased from 3 to 12 mg/d with 2- to 4-week intervals. Sample collections for prolactin were conducted before aripiprazole administration (baseline) and 2 to 4 weeks after the dose escalation of aripiprazole and just before next dose escalation. The samples were taken just before the morning dose. The plasma concentration of prolactin during aripiprazole administration (3, 6, 9, or 12 mg/d) was significantly lower than that at baseline. The mean (±SD) percent reductions at 3, 6, 9, and 12 mg/d were 35% ± 14%, 54% ± 17%, 57% ± 19%, and 63% ± 17%, respectively. However, neither the plasma concentration of prolactin nor the reduction ratio differed among the dosages of 6, 9, and 12 mg/d of aripiprazole. Three out of 8 patients with amenorrhea improved after 12 mg/d of aripiprazole. The present study suggests that adjunctive treatment with aripiprazole reduces the prolactin concentration that had been increased because of risperidone treatment. The effect occurs even when a low dosage (3 mg/d) of aripiprazole was used and achieves a plateau at dosages beyond 6 mg/d.

Hyperprolactinemia is a frequent consequence of treatment with some antipsychotic agents. Although prolactin secretion varies over the course of a day and during psychological circumstances, there is little information in the literature regarding the time dependence of the prolactin response to antipsychotics. We evaluated prolactin levels in schizophrenic patients receiving risperidone (3 mg twice daily), olanzapine (10 mg twice daily), or perospirone (16 mg twice daily) for at least 4 weeks. The subjects were compared to matched healthy controls. Plasma sample collection for quantification of drug and prolactin levels was conducted before and 2, 4, 6, 8, and 12 h after the morning dosing. Prolactin concentrations before dosing during risperidone treatment were significantly higher than during treatment with olanzapine and perospirone in females. The daily fluctuation of prolactin concentration after perospirone treatment was larger than that observed after risperidone and olanzapine treatments. Areas under the plasma concentration-time curves was greatest in subjects treated with risperidone, followed by perospirone and finally by olanzapine. These findings suggest that daily fluctuations in prolactin concentration after perospirone treatment are larger than following treatment with risperidone and olanzapine. The plasma concentration of prolactin during perospirone treatment therefore depends on the time of sampling. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Hyperprolactinemia is a frequent consequence of treatment with antipsychotic agents, partially because the prolactin response to antipsychotics is related to dopamine blockade. Recent studies have suggested that the prolactin response to olanzapine is weaker than that to risperidone. Thus, we studied the effects of various factors on the elevated plasma prolactin levels caused by these medications. The subjects were 94 patients with acutely exacerbated schizophrenia (46 males, 48 females). For four weeks, they received 6mg of risperidone and 20mg of olanzapine daily. Plasma samples were collected before the medications were given and 12h after the bedtime dosing each week. Treatment with either risperidone or olanzapine boosted plasma prolactin levels above baseline in both males and females. Prolactin levels were significantly higher in females than in males at all sampling points in both treatments. Risperidone increased prolactin significantly more than did olanzapine in both males and females. Delta prolactin (prolactin level at four weeks minus the baseline prolactin level) during olanzapine treatment significantly correlated with olanzapine concentration at 4th week (r =−0.518, p <0.01) only in males. Multiple regression analyses showed that delta prolactin during risperidone was significantly correlated with gender (p <0.001) and age (p <0.05) and that delta prolactin during olanzapine significantly correlated with gender (p <0.001) and drug concentration (p <0.01). The present study suggests that the predominant factors influencing hyperprolactinemia are young female for risperidone treatment, and being female and lower drug concentration as a predictor for hyperprolactinemia under olanzapine. [Copyright &y& Elsevier]