This study highlights the rare but significant risk of optic chiasm and brain herniation in patients with large prolactinomas undergoing treatment with dopamine agonists (DA). Two cases are presented: a 34-year-old woman and a 50-year-old man, both experiencing significant tumor size reduction and prolactin level decrease after DA therapy, but also developing complications such as medial temporal lobe herniation and inferior displacement tethering of the chiasm, respectively. These complications necessitated adjustments in treatment, including surgery and DA dose modification. The findings underscore the importance of vigilant monitoring, including neuro-ophthalmologic evaluation and timely MRI, especially within the first three months of DA therapy or upon new symptom onset. The study advocates for a personalized, multidisciplinary approach to managing DA therapy in prolactinoma patients, emphasizing the balance between effective tumor control and the prevention of serious complications. This contributes to the literature by detailing the management of rare DA therapy complications and suggesting a protocol for monitoring and intervention.