From the Guidelines
Monitoring prolactin levels is crucial in patients undergoing testosterone replacement therapy (TRT) because it helps identify potential underlying issues that could impact treatment outcomes, as recommended by the American Urological Association guideline 1. When evaluating patients for TRT, it is essential to consider the interplay between testosterone and prolactin levels. According to the guideline, serum prolactin levels should be measured in patients with low testosterone levels combined with low or low/normal luteinizing hormone levels 1. This is important because elevated prolactin levels may indicate underlying endocrine disorders, such as pituitary adenomas (prolactinomas), that could affect treatment outcomes.
Some key points to consider when monitoring prolactin levels in TRT patients include:
- Baseline prolactin levels should be checked before starting therapy and then monitored periodically, typically every 6-12 months or if symptoms develop
- Normal prolactin levels in men are generally below 15 ng/mL
- Elevated prolactin (hyperprolactinemia) can cause symptoms such as decreased libido, erectile dysfunction, infertility, and gynecomastia, which may overlap with those of low testosterone
- Hyperprolactinemia can result from various causes, including pituitary adenomas, medications, hypothyroidism, or as a feedback response to low testosterone
If elevated prolactin is detected during TRT, the clinician should investigate the cause and may need to adjust treatment accordingly, which could include adding dopamine agonists like cabergoline or bromocriptine if a prolactinoma is present, or modifying the TRT regimen, as suggested by the guideline 1. Therefore, monitoring prolactin levels is a critical component of TRT, and clinicians should prioritize this aspect of care to ensure optimal treatment outcomes and minimize potential complications.
From the Research
Importance of Prolactin Monitoring in Testosterone Replacement Therapy
- Prolactin levels can be affected by testosterone replacement therapy (TRT), and monitoring these levels is crucial to ensure effective treatment and minimize potential side effects 2.
- Testosterone replacement may stimulate hyperprolactinemia, which can lead to hypogonadism and other complications 2.
- The use of dopamine agonists, such as cabergoline, can help reduce prolactin levels and improve treatment outcomes in patients with prolactinomas 3, 4.
- In some cases, the concomitant use of cabergoline with an aromatase inhibitor can help maintain testosterone levels and restore normal sexual function without increasing prolactin levels 2.
Effects of Prolactin on Testosterone Replacement Therapy
- Elevated prolactin levels can interfere with the effectiveness of TRT, leading to reduced testosterone levels and hypogonadism 2, 3.
- The normalization of prolactin levels can improve treatment outcomes in patients with prolactinomas and hypogonadism 3, 4.
- The use of dopamine agonists and aromatase inhibitors can help optimize TRT and improve patient outcomes 2, 5.
Clinical Considerations
- Patients undergoing TRT should be monitored regularly for prolactin levels to ensure effective treatment and minimize potential side effects 2, 3.
- The selection of TRT method and dose adjustment should take into account the patient's prolactin levels and overall health status 6.
- The use of hepatotoxic androgens should be avoided, and alternative treatments, such as human chronic gonadotropin or aromatase inhibitors, may be considered in certain cases 6.