Hyperprolactinemia is a condition characterized by elevated levels of prolactin in the blood and causes symptoms of reduced sexual function and infertility in men and women. The causes of the occurrence of hyperprolactinemia are many, and the behavior is determined both by the underlying disease and by the presence of symptoms. The main regulator of prolactin secretion is dopamine, and its increase reduces the release of prolactin, and vice versa – low dopamine leads to high prolactin. The treatment of hyperprolactinemia is also based on this mechanism. Dopamine agonists are used, i.e. drugs that stimulate the increase of dopamine. Drug-induced hyperprolactinemia This is the most common cause of non-tumor-related elevation of prolactin. In most cases, this is a side effect of medications that block dopamine receptors in the brain. In up to 90% of cases during treatment with antipsychotics (phenothiazines, butyrophenones, risperidone), hyperprolactinemia may occur. Also when taking anticonvulsants, anti-depressants, anti-vomiting drugs, high blood pressure drugs and others. Although this type of hyperprolactinemia rarely causes complaints, sexual dysfunction and galactorrhea may occur. The first and most important step when taking such drugs is to determine whether the high prolactin is a side effect of the treatment or is due to another disease. It is recommended that the suspected medication be stopped and prolactin levels re-monitored. It usually takes about 3 days after stopping the drug for it to return to normal. In some cases, however, the underlying disease does not allow the ongoing treatment to be discontinued. An MRI of the head is then required to rule out a pituitary tumor causing the hyperprolactinemia. In the case of proven medical hyperprolactinemia and in the absence of complaints, no treatment is required. In the presence of symptoms, it is recommended to stop the medication that causes it, or to replace it with another one that has fewer side effects. For example, the antipsychotic aripiprazole reduces prolactin levels. Treatment with dopamine agonists on the background of antipsychotics is not recommended, as they can provoke psychotic episodes. If there is no other option to stop or replace the medication, a small dose of a dopamine agonist can be tried under the supervision of the treating psychiatrist. Treatment of prolactinomas A prolactinoma is a benign tumor (adenoma) of the pituitary gland that produces prolactin. It is also the only tumor that can be successfully treated with medication and does not necessarily require surgical treatment. First choice in the therapy of prolactinomas are dopamine agonists – cabergoline, bromocriptine and quinagolide. Cabergoline is most effective, leading to rapid normalization of prolactin levels, reduction in tumor size, restoration of sexual function and fertility, and cessation of galactorrhea.Treatment follow-up includes: Periodic measurement of prolactin levels, with the aim of adjusting the dose and achieving normal prolactin; Repeat pituitary MRI after 1 year or sooner in the presence of a macroprolactinoma (greater than 1 cm in diameter) and increasing prolactin levels despite ongoing treatment, or in the event of new symptoms (e.g. headache, visual disturbances, other hormonal abnormalities); In patients with macroprolactinomas, visual field monitoring is necessary because there is a risk of optic nerve compression; Evaluation and treatment of co-morbidities, such as reduced bone density or deficiencies of other pituitary hormones; In patients with microadenomas (less than 1 cm) and no complaints, treatment with cabergoline is not recommended. In amenorrhoea, as an alternative to the dopamine agonist, oral contraceptives can be taken. Treatment of prolactinoma can be discontinued after at least 2 years of treatment, when prolactin is already normal and there is no visible pituitary adenoma on MRI. In women with microadenomas who enter menopause, treatment can also be stopped, under periodic MRI control. After stopping therapy, prolactin was monitored every 3 months for the first year, then annually. If the levels rise, an MRI is required. Surgical treatment is required only as a last resort in patients who do not respond to a maximal dose of a dopamine agonist or who have aggressive adenomas that are growing and threatening surrounding brain structures. References: Melmed S, Casanueva FF, Hoffman AR, Kleinberg DL, Montori VM, Schlechte JA, Wass JA; Endocrine Society. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Feb;96(2):273-88. doi: 10.1210/jc.2010-1692. PMID: 21296991.After stopping therapy, prolactin was monitored every 3 months for the first year, then annually. If the levels rise, an MRI is required. Surgical treatment is required only as a last resort in patients who do not respond to a maximal dose of a dopamine agonist or who have aggressive adenomas that are growing and threatening surrounding brain structures. References: Melmed S, Casanueva FF, Hoffman AR, Kleinberg DL, Montori VM, Schlechte JA, Wass JA; Endocrine Society. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Feb;96(2):273-88. doi: 10.1210/jc.2010-1692. PMID: 21296991.After stopping therapy, prolactin was monitored every 3 months for the first year, then annually. If the levels rise, an MRI is required. Surgical treatment is only required as a last resort in patients who do not respond to a maximal dose of a dopamine agonist or who have aggressive adenomas that are growing and threatening surrounding brain structures. References: Melmed S, Casanueva FF, Hoffman AR, Kleinberg DL, Montori VM, Schlechte JA, Wass JA; Endocrine Society. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Feb;96(2):273-88. doi: 10.1210/jc.2010-1692. PMID: 21296991.