Olanzapine prolactin increase

Risperidone (1) has high affinity for D2, 5-HT2c and tti receptors and a very high affinity for the 5-HT2a receptor. Risperidone is the most likely of the atypical antipsychotics to cause prolactin increases, but has a lower weight gain liability than olanzapine or quetiapine. Risperidone has a relatively narrow therapeutic window since doses above 6 mg/day cause EPS in a dose-dependent manner. 

Effects, below. Newer antipsychotics such as olanzapine, quetiapine, and aripiprazole cause no or minimal increases of prolactin and reduced risks of extrapyramidal system dysfunction and tardive dyskinesia, reflecting their diminished D2 antagonism. 

Olanzapine can cause increased serum prolactin concentrations and galactorrhea, but probably to a lesser extent than haloperidol (SEDA-22, 65). 

There was a significant rise in baseline serum prolactin concentration in 10 patients after they had taken risperidone for a mean of 12 weeks compared with 10 patients who were tested after a neuroleptic drug-free wash-out period of at least 2 weeks (1014). A non-significant increase in serum prolactin has also been observed in an open comparison of risperidone with other neuroleptic drugs in 28 patients (1015). However, in a meta-analysis of two independent studies (n = 404), prolactin was greatly increased by risperidone (mean change 45-80 ng/ml), a larger effect than with olanzapine and haloperidol (1016). 

Clinical studies have demonstrated that olanzapine has a similar profile to clozapine without causing agranulocytosis preliminary studies also show that it does not cause extrapyramidal side effects or increase prolactin release. Olanzapine has recently been introduced for the treatment of mania. 

In an 8-week study, pre-school-age children with bipolar disorder (aged 4-6 years) took either olanzapine (n = 15 mean age 5.0 years 10 boys mean dose 6.3 mg/day) or risperidone (n = 16 mean age 5.3 years 12 boys mean dose 1.4 mg/day) (59). There were significantly more dropouts with olanzapine (6 versus 1), including one patient who withdrew because of adverse events (increased appetite and hand tremor). The main adverse events, found with both treatments, were significant increases in prolactin concentrations and weight gain. With both treatments, increased appetite, flu-like symptoms, headaches, and sedation were the most commonly reported adverse effects. 

Endocrine Aripiprazole is said to stabilize the dopaminergic system and thus ameliorate schizophrenic symptoms without increasing serum prolactin [SEDA-31, 76]. Prolactin concentrations and sexual function in schizophrenic patients have been evaluated in an open, 26-week, multicenter study, in which 555 patients were randomized to aripiprazole ( = 284) or standard care (olanzapine, quetiapme, or risperidone n = 271) [69 ]. At 8 weeks, those who took aripiprazole reported significantly greater improvement in sexual function. Baseline mean serum prolactin concentrations were similar in the two groups (434 and 423 mg/1 respectively) however, at week 26, the mean fall in serum prolactin was 342 mg/1 with aripiprazole compared with 133 mg/1 with the other treatments. 

Observational studies The use of antipsychotic drugs in children and adolescents is of particular concern. In a 24-week, multicenter, open study supported by Eli-Lilly, the marketing authorization holder, 96 adolescents with schizophrenic disorder (mean age 16 years 68% boys) were given olanzapine 10 mg/day [83 ]. BPRS scores fell from baseline to week 6 by a mean of 17. The most common adverse events were weight gain and increased prolactin. Weight... 

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