PRL and hyperprolactinemia: Table 2 summarized the characteristics of the five included studies. Of the two excluded, one study was not blind, and the other one did not report method of randomization. Four studies included patients treated in one center; another one was a multi-center study. The diagnosis of hyperprolactinemia was made from the laboratory tests for serum prolactin level (Table 1), in addition there were two studies reported the prolactin-related adverse events.