The frequency of the occurrence of movement disorder has especially decreased with the use of second-generation antipsychotics. The second-generation antipsychotics are generally effective in treating the positive as well as negative symptoms of schizophrenia, influencing the serotonergic and dopaminergic system receptors [Tajima et al. 2009; Blanc et al. 2010]. The mechanisms of many side effects

of the antipsychotics are described as receptor blockage. For example, the extrapyramidal symptoms (EPSs) similar to Parkinson’s disease appear to be dependent on decreased dopamine activity through dopamine Inhibitors,research,lifescience,medical receptor blockage in the nigrostriatal pathway; however, dopamine blockage in the hypothalamic and pituitary systems has resulted in hyperprolactinemia [Pramyothin and Khaodhiar, 2010]. Most second-generation antipsychotics do not cause a sustained elevation in prolactin levels, whereas Inhibitors,research,lifescience,medical antipsychotic-induced hyperprolactinemia is almost universal with first-generation antipsychotics agents. The reason for the use of the second-generation antipsychotics has been reduced EPSs and also endocrinological side Inhibitors,research,lifescience,medical effects, due to their influence on the positive and negative symptoms of schizophrenia [Newcomer, 2005; Coccurello and Moles, 2010; Kurt et al. 2008]. A typical drug is risperidone, a derivative of benzoxazole that shows

affinity for 5-HT2A serotonin receptors (5-HT2A) and for D2-dopamine receptors (D2), together with H1-histamine (H1) receptor, Inhibitors,research,lifescience,medical alpha -1 and alpha-2 adrenergic receptor blockade. Risperidone is unique among most other ‘atypicals’ in that it has high affinity for the D2 receptor. The affinity of risperidone for 5-HT2A is 10–20 times more than for the D2 receptor. The most common side merely effects are EPSs, weight gain, hyperprolactinemia, orthostatic hypotension and somnolence [Komossa et al. 2011]. Endocrinological system side effects are not limited to the increase in prolactin and the impaired glucose tolerance test and diabetes mellitus have also been recorded Inhibitors,research,lifescience,medical [Kim et al. 2002]. Many antipsychotics are

known to cause hyperprolactinemia, Batimastat which may lead to hypogonadism-induced osteoporosis, galactorrhoea, gynaecomastia (male breast development), irregular menstruation and sexual dysfunction. Risperidone is one of the second-generation antipsychotics most likely to induce hyperprolactinemia, whereas this is infrequently and only transiently associated with other second-generation antipsychotics. Women are more sensitive than men to these effects and risperidone-induced hyperprolactinemia is at least at a similar level to that found with the first-generation antipsychotics [Halbreich et al. 2003]. Acromegaly, a growth hormone (GH)-secreting pituitary adenoma, is due to chronic GH hypersecretion [Melmed et al. 2005]. At diagnosis, about 75% of patients have macroadenomas.