From the Guidelines
Cabergoline should be considered for use in men undergoing hormone replacement therapy (HRT) with testosterone only when there is evidence of hyperprolactinemia, as it can help mitigate prolactin-related side effects. When men use testosterone, especially at higher doses or for extended periods, some may experience elevated prolactin levels which can lead to symptoms like gynecomastia (breast tissue growth), decreased libido, or erectile dysfunction. According to a study published in the Annals of Internal Medicine 1, combining therapies such as cabergoline with other treatments can result in greater improvements in erectile function. Cabergoline, typically prescribed at 0.25-0.5mg taken once or twice weekly, works by acting as a dopamine agonist that reduces prolactin secretion from the pituitary gland.
- Key considerations for the use of cabergoline in this context include:
- It should only be used when blood tests confirm elevated prolactin levels, not preventatively.
- The typical approach is to start with 0.25mg once weekly, then adjust based on follow-up prolactin testing after 4-8 weeks.
- Side effects may include nausea, dizziness, and headaches.
- Regular monitoring of prolactin levels, testosterone levels, and potential side effects is essential while using this medication as part of an HRT protocol. It's crucial to note that cabergoline use should be supervised by a healthcare provider familiar with hormone management, as inappropriate use without confirmed hyperprolactinemia could disrupt other hormonal systems. The evidence from studies like the one published in the Annals of Internal Medicine 1 supports the careful consideration of cabergoline in managing side effects associated with testosterone therapy, emphasizing the importance of a personalized approach based on individual patient needs and hormonal profiles.
From the Research
Use of Cabergoline in HRT in Men Using Testosterone
- Cabergoline is a dopamine agonist that has been used to treat hyperprolactinemia, a condition that can cause hypogonadism and infertility in men 2, 3, 4.
- In men with prolactinoma, cabergoline treatment has been shown to rapidly improve gonadal function, including testosterone levels and sperm count 3, 4.
- The use of cabergoline in combination with testosterone replacement therapy has been reported to be effective in treating hypogonadism in men with prolactinoma, without stimulating hyperprolactinemia 2.
- Cabergoline has been compared to bromocriptine, another dopamine agonist, and has been shown to be more effective and better tolerated in treating hyperprolactinemic males 4.
- The safety and efficacy of cabergoline in men with prolactinoma have been demonstrated in several studies, with significant reductions in prolactin levels and tumor size, and improvements in testosterone levels and sexual function 2, 3, 4.
Mechanism of Action
- Cabergoline works by binding to dopamine D2 receptors, which inhibits the secretion of prolactin and restores normal pituitary function 5.
- The use of cabergoline in combination with an aromatase inhibitor, such as anastrozole, has been reported to be effective in treating men with prolactinoma who are also receiving testosterone replacement therapy, by preventing the aromatization of testosterone to estradiol and subsequent estrogen-stimulated prolactin release 2.
Clinical Evidence
- A study of 41 men with macroprolactinoma and 10 men with microprolactinoma found that 24 months of cabergoline treatment resulted in significant reductions in prolactin levels and tumor size, and improvements in testosterone levels and sexual function 3.
- Another study of 17 men with macroprolactinoma found that cabergoline treatment for 6 months resulted in significant improvements in seminal fluid parameters and sexual function, compared to bromocriptine treatment 4.