Initial Treatment for Hyperprolactinemia
Cabergoline is the first-line treatment for hyperprolactinemia due to its superior effectiveness in normalizing prolactin levels and better adverse effect profile compared to other dopamine agonists. 1
Diagnostic Considerations Before Treatment
- Before initiating treatment, exclude other causes of hyperprolactinemia such as pregnancy, primary hypothyroidism, and medication-induced hyperprolactinemia 1
- Assess baseline macroprolactin levels when serum prolactin is mildly or incidentally elevated to rule out macroprolactinemia 1
- For patients with large pituitary lesions but normal or mildly elevated prolactin levels, perform serial dilutions of serum prolactin measurement to detect the "high-dose hook effect" 1
First-Line Treatment: Cabergoline
- Cabergoline has higher affinity for dopamine receptors and superior efficacy in normalizing prolactin (83% vs 59% for bromocriptine) 1, 2
- Standard initial dosing of cabergoline:
Monitoring During Treatment
- Obtain a baseline echocardiogram before initiating cabergoline treatment 4, 5
- For patients on standard doses (≤2 mg/week), echocardiographic surveillance every 5 years is recommended 4, 3
- For patients on higher doses (>2 mg/week), annual echocardiography is recommended to monitor for cardiac valvulopathy 4, 3, 5
- Monitor for potential cerebrospinal fluid leak (rhinorrhea) due to medication-induced tumor shrinkage, particularly in tumors that have invaded sphenoid bone 1
Managing Side Effects
- Small nocturnal dose increments can reduce gastrointestinal intolerance and postural hypotension 3
- Be aware of psychological side effects (mood changes, depression, aggression, hypersexuality, impulse control disorders) which are dose-independent and may be more common in children and adolescents 3
Treatment Resistance
- For patients resistant to standard cabergoline doses, offer graduated dose increments up to 3.5 mg/week 1, 3
- In exceptional cases, doses up to 7 mg/week may be considered 1, 3
- Dopamine agonist resistance is defined as failure to achieve normal prolactin levels and/or less than 50% reduction in tumor area after 3-6 months of maximally tolerated doses 3
Second-Line Options
- Consider bromocriptine as an alternative dopamine agonist, though it has lower efficacy (58% vs 83% normalization of prolactin) and more adverse effects (72% vs 52%) compared to cabergoline 2, 6
- Surgical intervention (transsphenoidal surgery) may be considered when a patient is unable to tolerate or is resistant to high-dose cabergoline, or when a patient develops deteriorating vision on cabergoline 1
- Radiotherapy is reserved for exceptional cases with growing prolactinoma where other treatments have failed 1
Treatment Duration and Discontinuation
- If prolactin levels have been normalized for at least 2 years on medical therapy and there is no visible residual prolactinoma on MRI, consider gradual cabergoline dose reduction 4
- Continue monitoring serum prolactin for at least 2 more years after treatment discontinuation 4
- Relapse rates after discontinuation vary (20-30%), particularly when residual adenoma exists 7
Special Considerations
- For pregnant patients or those planning pregnancy, bromocriptine may be preferred due to more extensive safety data during pregnancy 8, 9
- FDA warning: Cabergoline should be used with caution in patients with a history of cardiac or extracardiac fibrotic disorders 5
- Avoid dopamine agonists in patients with pregnancy-induced hypertension unless the potential benefit outweighs the possible risk 5, 10