Echocardiography and monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia: a joint position statement of the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology

Approach to the Patient With Prolactinoma

Prolactinomas are the most common pituitary tumor histotype, with microprolactinomas being prevalent in women and macroprolactinomas in men. Hyperprolactinemia is among the most common causes of hypogonadotropic hypogonadism in both sexes, prompting medical advice for hypogonadism (infertility, oligo-amenorrhea, impotence, osteoporosis/osteopenia) in both sexes, and for signs and symptoms of mass effects (hypopituitarism, visual loss, optic chiasm compression, cranial nerve deficits, headaches) predominantly in men. Diagnostic workup involves a single prolactin measurement and pituitary imaging, but some laboratory artifacts (ie, the "hook effect" and macroprolactin) can complicate or delay the diagnosis. The treatment of choice for prolactinomas is represented by dopamine agonists, mainly cabergoline, which are able to induce disease control, restore fertility in both sexes, and definitively cure one-third of patients, thus permitting treatment discontinuation. Pregnancy and menopause may promote spontaneous prolactin decline and anticipate cabergoline discontinuation in women. Surgery and/or radiotherapy are indicated in case of resistance to cabergoline not overcome by the increase in drug dose up to the maximally tolerated or the patient's personal choice of surgery. The evidence of resistance to cabergoline in invasive and proliferative tumors may indicate biological aggressiveness, thus requiring alternative therapeutic approaches mainly based on temozolomide use as monotherapy or combined with radiotherapy. In uncontrolled patients, new medical approaches (alternative hormonal treatments, cytotoxic drugs, peptide receptor radionuclide therapy, mTOR/Akt inhibitors, tyrosine kinase inhibitors, or immunotherapy) may be offered but the experience collected to date is still very scant. This article reviews different facets of prolactinomas and discusses approaches to the condition in more common clinical situations.

Guidance on the treatment of antipsychotic-induced hyperprolactinemia when switching the antipsychotic is not an option

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Purpose

This article aims to evaluate management options for antipsychotic-induced hyperprolactinemia and associated treatment considerations such as efficacy, tolerability, drug interactions, contraindications, and dosing regimens.

Summary

Hyperprolactinemia is a common adverse effect of antipsychotics. First-line management includes reducing the dose of the offending antipsychotic, discontinuing the antipsychotic, or switching to another antipsychotic associated with a lower risk of hyperprolactinemia. However, these options are not always practical and are associated with a risk of relapse of the psychiatric illness. Other management options include adjunctive aripiprazole, dopamine agonists (cabergoline and bromocriptine), metformin, and herbal supplements. A search of Embase, PubMed, and Google Scholar using key terms such as hyperprolactinemia, prolactin, antipsychotic, treatment guidelines, aripiprazole, dopamine agonist, cabergoline, bromocriptine, metformin, herbals, supplements, and medications was conducted for literature retrieval. Upon evaluation of the available literature we found the following: (1) aripiprazole is safe and effective in lowering prolactin levels within normal limits; (2) adjunctive cabergoline and bromocriptine decrease elevated prolactin levels, while cabergoline may be more effective in reducing prolactin but can also be associated with a more serious adverse effect of cardiac valvular abnormalities; (3) metformin causes a mild reduction of prolactin levels; and (4) there are limited data to support use of herbal medications (chamomile, Peony-Glycyrrhiza decoction, and shakuyaku-kanzo-to) in antipsychotic-induced hyperprolactinemia

Conclusion

There are treatments available for antipsychotic-induced hyperprolactinemia in patients who are unable to alter their current antipsychotic regimen. However, there remains a need for additional short- and long-term studies to determine the efficacy and safety of these treatment strategies, given that patients taking antipsychotics typically require chronic, life-long treatment for their illnesses.

Incidence of Cabergoline-Associated Valvulopathy in Primary Care Patients With Prolactinoma Using Hard Cardiac Endpoints

BACKGROUND

Controversy exists as to whether low-dose cabergoline is associated with clinically significant valvulopathy. Few studies examine hard cardiac endpoint data, most relying on echocardiographic findings.

OBJECTIVES

To determine the prevalence of valve surgery or heart failure in patients taking cabergoline for prolactinoma against a matched nonexposed population.

DESIGN

Population-based cohort study based on North East London primary care records.

METHODS

Data were drawn from ~1.5 million patients' primary care records. We identified 646 patients taking cabergoline for >6 months for prolactinoma. These were matched to up to 5 control individuals matched for age, gender, ethnicity, location, diabetes, hypertension, ischemic heart disease, and smoking status. Cumulative doses/durations of treatment were calculated. Cardiac endpoints were defined as cardiac valve surgery or heart failure diagnosis (either diagnostic code or prescription code for associated medications).

RESULTS

A total of 18 (2.8%) cabergoline-treated patients and 62 (2.33%) controls reached a cardiac endpoint. Median cumulative cabergoline dose was 56 mg (interquartile range [IQR] 27-123). Median treatment duration was 27 months (IQR 15-46). Median weekly dose was 2.1 mg. Neither univariate nor multivariate analysis demonstrated a significant association between cabergoline treatment at any cumulative dosage/duration and an increased incidence of cardiac endpoints. In a matched analysis, the relative risk for cardiac complications in the cabergoline-treated group was 0.78 (95% CI, 0.41-1.48; P = 0.446). Reanalysis of echocardiograms for 6/18 affected cabergoline-treated patients showed no evidence of ergot-derived drug valvulopathy.

CONCLUSIONS

The data did not support an association between clinically significant valvulopathy and low-dose cabergoline treatment and provide further evidence for a reduction in frequency of surveillance echocardiography.

The risks of medical treatment of prolactinoma

First-line treatment of prolactinoma is usually medical, based on dopamine agonists receptors, mainly cabergoline. The classical side-effects of cabergoline (low blood pressure and nausea) have been well known since it was first introduced. Other side-effects, however, are more controversial or simply less frequent, but need to be considered during monitoring. This review will focus on these side-effects: cardiac valvular fibrosis, pleural, pericardial and retroperitoneal fibrosis, addictive/compulsive behaviors, and risks secondary to significantly decreased tumor volume. We will also describe how such side-effects should be monitored and managed. In our opinion, the low prevalence of these side-effects should not cast doubt on the role of cabergoline in the therapeutic algorithm of prolactinoma.

Monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia

The surveillance strategy for patients taking low dose cabergoline for hyperprolactinaemia is controversial. As more evidence has emerged that the risks of cardiac valvulopathy in this population of patients are low, fewer and fewer endocrinologists adhere strictly to the original medicines and healthcare products agency MHRA guidance of "at least" annual echocardiography. Strict adherence to this guidance would be costly in monetary terms (£5.76 million/year in the UK) and also in resource use (90,000 extra echocardiograms/year). This article reviews the proposed pathophysiological mechanism underlying the phenomenon of dopamine agonist valvulopathy, the characteristic echocardiographic changes seen, summarises the published literature on the incidence of valvulopathy with low dose cabergoline and examines the previous and current evidence-based screening guidelines.

Hyperprolactinaemia

Hyperprolactinaemia is one of the most common problems in clinical endocrinology. It relates with various aetiologies (physiological, pharmacological, pathological), the clarification of which requires careful history taking and clinical assessment. Analytical issues (presence of macroprolactin or of the hook effect) need to be taken into account when interpreting the prolactin values. Medications and sellar/parasellar masses (prolactin secreting or acting through “stalk effect”) are the most common causes of pathological hyperprolactinaemia. Hypogonadism and galactorrhoea are well-recognized manifestations of prolactin excess, although its implications on bone health, metabolism and immune system are also expanding. Treatment mainly aims at restoration and maintenance of normal gonadal function/fertility, and prevention of osteoporosis; further specific management strategies depend on the underlying cause. In this review, we provide an update on the diagnostic and management approaches for the patient with hyperprolactinaemia and on the current data looking at the impact of high prolactin on metabolism, cardiovascular and immune systems.

The epidemiology, diagnosis and treatment of Prolactinomas: The old and the new

Prevalence and incidence of prolactinomas are approximately 50 per 100,000 and 3-5 new cases/100,000/year. The pathophysiological mechanism of hyperprolactinemia-induced gonadotropic failure involves kisspeptin neurons. Prolactinomas in males are larger, more invasive and less sensitive to dopamine agonists (DAs). Macroprolactin, responsible for pseudohyperprolactinemia is a frequent pitfall of prolactin assay. DAs still represent the primary therapy for most prolactinomas, but neurosurgery has regained interest, due to progress in surgical techniques and a high success rate in microprolactinoma, as well as to some underestimated side effects of long-term DA treatment, such as impulse control disorders or impaired quality of life. Recent data show that the suspected effects of DAs on cardiac valves in patients with prolactinomas are reassuring. Finally, temozolomide has emerged as a valuable treatment for rare cases of aggressive and malignant prolactinomas that do not respond to all other conventional treatments.