Prolactin-related adverse events

Similarly, risperidone caused extrapyramidal symptoms in fewer patients (24%) than haloperidol did (43%) in a two-phase study in patients with acute bipolar mania (phase I, 3 weeks, patients receiving either risperidone 1-6 mg/day, haloperidol 2-12 mg/day, or placebo (32). Plasma prolactin concentration was higher with risperidone (no data provided) prolactin-related adverse events included non-puerperal lactation, breast pain, dysmenorrhea, and reduced libido or sexual dysfunction these effects occurred in six patients on risperidone (4%) and in two on haloperidol (1.3%). 

In the second study, which lasted 2 years, long-acting injectable risperidone (n = 50) was compared with oral risperidone (n = 47) and haloperidol (n = 47) [130. Prolactin-related adverse events occurred in four of those who received injectable risperidone galactorrhea in one amenorrhea... 

In 50 patients with newly diagnosed schizophrenia (mean age 25 years) who were treated with injectable risperidone 25-50 mg every 2 weeks for 2 years [132 ], prolactin concentrations increased in 18 patients, four of whom reported possible prolactin-related adverse events (amenorrhea in one galactorrhea in one amenorrhea and galactorrhea in one amenorrhea and delayed menses in one). Mean increase in body mass index was 4.8 kg/m 10 subjects required anticholinergic medication, and one developed persistent dyskinesia. 

Observational Studies A 12-week, open-label study of 58 patients receiving risperidone randomised to continue with risperidone or switch to paliperidone ER found a side-effect profile for paliperidone ER similar to that of risperidone, including metabolic problems and prolactin-related adverse events [18 ]. 

In a randomized, double-blind, multicenter comparison of amisulpride 1000 mg/day (n = 70) and flupenthixol 25 mg/day (n = 62) for 6 weeks, the two drugs significantly improved the acute psychotic symptoms to a similar extent (32). The total numbers of dropouts were 19 with amisulpride and 25 with flupenthixol. Adverse effects accounted for 8.6 and 18% respectively of the totals. Amisulpride caused significantly fewer extrapyramidal adverse effects. Apart from the extrapyramidal adverse effects, there were treatment-related adverse events in 87% of the patients given amisulpride and 92% of those given flupenthixol. Prolactin concentrations were higher with amisulpride. 

The relation of prolactin concentrations and certain adverse events has been explored in large randomized, double-blind studies. In 813 women and 1912 men, haloperidol produced dose-related increases in plasma prolactin concentrations in men and women, but they were not correlated with adverse events such as amenorrhea, galactorrhea, or reduced libido in women or with erectile dysfunction, ejaculatory dysfunction, gynecomastia, or reduced libido in men (470). 

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