In clinical studies, bromocriptine has had small and variable effects on ACTH secretion in patients with CD [50]. In contrast, a 2004 study demonstrated significant in vitro inhibition of ACTH secretion with cabergoline in 100 % of cases with confirmed D2 receptor expression, and significant in vivo reduction of cortisol levels in 60 % of cases—with 40 % normalization of cortisol secretion [48]. Altogether, 3 small, non-randomized studies (one with a long-term follow-up publication) have found evidence have found evidence for efficacy of cabergoline in this setting [48, 52, 53].