New insights in the management of antipsychotics in the treatment of schizophrenia in a patient with prolactinoma: a case report and review of the literature

Determining Ideal Management for Patients With Coexisting Prolactinomas and Psychiatric Symptoms: A Systematic Review

OBJECTIVE

Prolactinomas-pituitary tumors that overproduce prolactin-can cause various troublesome symptoms. Dopamine agonists (DAs) reduce prolactin production in the prolactin pathway, making them the first-line treatment for prolactinomas. However, the main side effect of DA treatment, hyperdopaminergia, is an explicit etiology for psychiatric side effects. Psychiatric conditions are often treated with dopamine antagonists, which can induce hyperprolactinemia. This presents a challenge for patients with both a prolactinoma and a preexisting psychiatric condition, as treatment of one condition could worsen the other. This review seeks to identify an adequate therapeutic regimen for patients with coexisting prolactinomas and psychiatric symptoms.

METHODS

This review examined PubMed citations from 1960 to 2023 published in English and involving human subjects. Case reports, case series, and cohort studies involving patients with concomitant prolactinomas and psychiatric symptoms, as validated by brain imaging, serologic prolactin levels, and medical history or chart reports of psychiatric symptoms, were included.

RESULTS

Thematic analysis included 23 reports involving 42 participants; 27 of the 42 patients experienced a significant reduction in prolactin levels and psychiatric symptoms (64%). Treatment of those 42 patients included discontinuing or altering antipsychotic/dopamine antagonist therapy or discontinuing DA therapy to reduce psychiatric symptoms, with surgery or radiation postpharmacotherapy as a last-line strategy. However, in some cases (reported in Tables 2 to 4), either psychiatric or prolactin-related symptoms recurred despite adjustment.

CONCLUSIONS

Clinicians may find it beneficial to prioritize specific antipsychotics (aripiprazole, olanzapine, ziprasidone, or clozapine) over others (risperidone, thioridazine, thiothixene, and remoxipride). Discontinuing DA medication at least periodically until the patient's condition improves may also be advisable. If these 2 initial approaches do not yield a significant improvement in symptom management, surgery or radiation therapy may be considered. As patients may respond differently to these therapies, our study still recommends a patient-centered approach.

Treatments of psychiatric disorders, hyperprolactinemia and dopamine agonists

While the prevalence of hyperprolactinemia under antidepressants is very low, its prevalence under antipsychotics, particularly of the first generation, is high. Antipsychotics act by blocking dopamine activity at the level of the dopamine type 2 receptor (D2R). When prolactin levels exceed 80-100 ng/ml, a pituitary adenoma must be ruled out by MRI. Treatment of hyperprolactinemia is necessary only in cases with clinical symptoms of hypogonadism. Three treatment options are possible: switch to a less hyperprolactinemic antipsychotic, sex steroid supplementation or dopamine agonist (which normalizes prolactin levels in only half of cases). Fortunately, psychotic exacerbation due to the opposing effects of antipsychotics and dopamine agonists on the D2R seems very rare. When a patient presents with a macroprolactinoma, particularly with optic chiasm compression, surgery or dopamine agonists may be proposed. The agonists are effective in reducing tumor mass and improving visual defects in the majority of patients but rarely normalize prolactin levels.

Controversial issues in the management of hyperprolactinemia and prolactinomas - An overview by the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism

Prolactinomas are the most common pituitary adenomas (approximately 40% of cases), and they represent an important cause of hypogonadism and infertility in both sexes. The magnitude of prolactin (PRL) elevation can be useful in determining the etiology of hyperprolactinemia. Indeed, PRL levels > 250 ng/mL are highly suggestive of the presence of a prolactinoma. In contrast, most patients with stalk dysfunction, drug-induced hyperprolactinemia or systemic diseases present with PRL levels < 100 ng/mL. However, exceptions to these rules are not rare. On the other hand, among patients with macroprolactinomas (MACs), artificially low PRL levels may result from the so-called "hook effect". Patients harboring cystic MACs may also present with a mild PRL elevation. The screening for macroprolactin is mostly indicated for asymptomatic patients and those with apparent idiopathic hyperprolactinemia. Dopamine agonists (DAs) are the treatment of choice for prolactinomas, particularly cabergoline, which is more effective and better tolerated than bromocriptine. After 2 years of successful treatment, DA withdrawal should be considered in all cases of microprolactinomas and in selected cases of MACs. In this publication, the goal of the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism (SBEM) is to provide a review of the diagnosis and treatment of hyperprolactinemia and prolactinomas, emphasizing controversial issues regarding these topics. This review is based on data published in the literature and the authors' experience.