What is the starting dose of Cabergoline (Dopamine Agonist)?

Starting Dose of Cabergoline for Prolactinoma Treatment

The recommended starting dose of cabergoline for prolactinoma treatment is 0.25 mg twice weekly (0.5 mg/week total). 1

Dosing Guidelines

Initial Dosing

• Start with 0.25 mg twice weekly for the first 4 weeks 2, 1
• Administer at night to reduce side effects such as gastrointestinal intolerance and postural hypotension 2
• Perform baseline cardiovascular evaluation before initiating treatment 1
• Consider baseline echocardiography to assess for valvular disease 1, 3

Dose Titration

• Increase dose by 0.25 mg twice weekly increments 1
• Allow at least 4 weeks between dose adjustments to properly assess response 1
• Titrate up to a maximum of 1 mg twice weekly (2 mg/week) for most patients 2, 1
• For resistant cases, doses may be increased up to 3.5 mg/week, or in exceptional cases up to 7 mg/week 3, 2

Monitoring and Follow-up

Prolactin Monitoring

• Assess serum prolactin levels to determine response to therapy
• Continue titration until prolactin normalizes or maximum tolerated dose is reached
• Once normal prolactin levels are maintained for 6 months, consider dose reduction or discontinuation 1

Cardiac Monitoring

• For patients receiving ≤2 mg/week: Echocardiography every 5 years 3
• For patients receiving >2 mg/week: Annual echocardiography 3
• This monitoring is particularly important as cumulative doses can potentially lead to cardiac valvulopathy, although this is more common with higher doses used in Parkinson's disease 3

Efficacy and Response

Cabergoline is highly effective in treating prolactinomas:

• Normalizes prolactin levels in 86% of all patients 4
• 92% effectiveness in microprolactinomas (<10mm) 4
• 77% effectiveness in macroprolactinomas (≥10mm) 4
• Superior to bromocriptine in normalizing prolactin (83% vs 59%) with fewer adverse events (52% vs 72%) 3, 5

Special Considerations

Resistant Cases

• Resistance is defined as failure to achieve normal prolactin levels and/or less than 50% tumor shrinkage after 3-6 months on ≥2 mg/week 2
• For resistant cases, consider:
  1. Increasing dose up to 3.5-7 mg/week 3, 2
  2. Surgical intervention if medical therapy fails 3

Adverse Effects

• Most common: Nausea, dizziness, headache (typically mild and transient) 5, 6, 7
• Serious but rare: Cerebrospinal fluid leak after tumor shrinkage, particularly in tumors invading the sphenoid bone 3
• Psychological effects: Mood changes, depression, hypersexuality (can occur at any dose) 2

Treatment Duration

• After normal prolactin levels are maintained for 6 months, consider discontinuation with periodic monitoring 1
• If prolactin levels remain normal for at least 2 years and MRI shows no visible residual tumor, consider gradual dose reduction and eventual discontinuation 3
• Continue monitoring prolactin levels for at least 2 years after discontinuation 3

Cabergoline's long half-life (63-109 hours) allows for twice-weekly dosing, improving compliance compared to other dopamine agonists that require daily administration 8.