Quick Overview
- Bromocriptine is a low‑cost dopamine agonist that can lower growth‑hormone (GH) levels in many patients with acromegaly.
- It is usually added when surgery or first‑line somatostatin analogues are insufficient or not tolerated.
- Typical dose starts at 2.5mg daily and may be increased to 10mg or more, split across doses.
- Common side‑effects include nausea, dizziness, and low blood pressure; most are manageable with dose adjustments.
- Long‑term monitoring of IGF‑1 and MRI scans remains crucial, regardless of medication choice.
What Is Bromocriptine?
Bromocriptine is a synthetic ergot derivative that acts as a dopamine‑2 (D2) receptor agonist. It was first approved in the 1970s for treating hyperprolactinemia and Parkinson’s disease, and later repurposed for endocrine disorders where lowering GH secretion is needed.
By stimulating D2 receptors on pituitary somatotroph cells, bromocriptine suppresses the pulsatile release of GH, which in turn reduces circulating insulin‑like growth factor‑1 (IGF‑1). The drug is taken orally, making it convenient compared with injectable options.
Acromegaly at a Glance
Acromegaly is a chronic disorder caused by excessive secretion of growth hormone (GH) from a pituitary adenoma. The resulting high levels of IGF‑1 lead to tissue overgrowth, enlarged facial features, joint pain, and metabolic complications such as insulin resistance.
The disease prevalence is roughly 60cases per million worldwide, with a median diagnostic delay of 5-10years-often because early symptoms are subtle.
Why Choose a Dopamine Agonist?
Medical therapy for acromegaly follows three main pathways: surgery, radiotherapy, and drugs. When surgery (usually transsphenoidal resection) fails to cure the disease or the tumor is not resectable, doctors turn to medication.
Historically, Somatostatin analogues (e.g., octreotide, lanreotide) have been the first‑line drugs because they suppress GH in up to 70% of patients. However, not everyone tolerates injectable somatostatin analogues-some experience gallstones or severe gastrointestinal upset.
Enter dopamine agonists such as bromocriptine or cabergoline. About 20‑30% of acromegaly patients have tumors that express dopamine receptors, making them responsive to this class. For those patients, a dopamine agonist can be a cheaper, oral alternative.
How Effective Is Bromocriptine?
Effectiveness is measured by two markers: serum IGF‑1 normalisation and tumour size reduction on MRI. Clinical series from the UK, the US, and the Middle East report the following:
- IGF‑1 falls into the normal range in roughly 25‑35% of patients on bromocriptine monotherapy.
- When combined with a somatostatin analogue, the normalisation rate rises to 45‑55%.
- Tumour shrinkage >20% is observed in about 15% of responders, usually after 12-18months of treatment.
These numbers are lower than those for pegvisomant (a GH‑receptor blocker) or first‑generation somatostatin analogues, but the oral route and low price make bromocriptine attractive for long‑term management, especially in resource‑limited settings.
Starting and Titrating the Dose
Therapeutic dosing follows a gradual titration schedule to limit side‑effects:
- Day1-3: 2.5mg once daily at bedtime.
- Day4-7: Increase to 5mg daily (2.5mg twice daily).
- Weeks2-4: If IGF‑1 remains high and side‑effects are tolerable, raise to 7.5mg daily.
- Beyond Week4: Some patients reach 10mg/day, split into 5mg twice daily.
Monitoring IGF‑1 every 6-8weeks guides whether further escalation is needed. If nausea or hypotension becomes problematic, clinicians often split the daily dose into three smaller administrations and advise taking the drug with food.
Side‑Effects and Safety Profile
Common adverse events include nausea, vomiting, headache, dizziness, and orthostatic hypotension. Most are dose‑dependent and improve after the first few weeks.
Less frequent but serious concerns are:
- Valvular heart disease - rare, but higher‑dose ergot derivatives have been linked to fibrotic valvulopathy.
- Psychiatric symptoms - hallucinations or impulse‑control issues have been reported, especially in patients with pre‑existing mood disorders.
Routine echocardiograms are not mandatory for every patient, but baseline cardiac evaluation is recommended for those with a history of cardiovascular disease.
How Bromocriptine Fits Into the Overall Treatment Landscape
The choice of therapy often follows a decision tree:
| Medication | Mechanism | Administration | IGF‑1 Normalisation (%) | Typical Side‑Effects |
|---|---|---|---|---|
| Bromocriptine | Dopamine‑2 receptor agonist | Oral tablets | 25-35% | Nausea, hypotension, headache |
| Octreotide | Somatostatin analogue | Subcutaneous or long‑acting IM | 50-70% | Gallstones, GI upset, hyperglycaemia |
| Pegvisomant | GH‑receptor antagonist | Daily subcutaneous injection | >90% | Injection site reactions, liver‑function changes |
| Cabergoline | Dopamine‑2 receptor agonist (long‑acting) | Oral tablets | 30-40% | Nausea, dizziness, potential valvulopathy |
From the table, bromocriptine emerges as the most affordable oral option, but its efficacy sits below that of octreotide and pegvisomant. For patients who cannot afford injectables or who have contraindications to somatostatin analogues, bromocriptine (or its longer‑acting cousin cabergoline) becomes a sensible second‑line choice.
Monitoring and Long‑Term Management
Regardless of medication, the following follow‑up schedule is widely endorsed by endocrine societies:
- IGF‑1 and GH: every 3months for the first year, then every 6-12months.
- MRI of the pituitary: baseline, then 12months after initiating therapy, and thereafter based on tumour behaviour (usually every 2-3years).
- Cardiovascular assessment: annual BP check, ECG if patient reports dizziness.
- Metabolic profile: fasting glucose and lipid panel every 6months, since acromegaly raises diabetes risk.
Patients on bromocriptine should have orthostatic blood pressure measured after dose titration to catch hypotension early.
Special Populations and Practical Tips
Pregnant women with acromegaly are a rare but important group. Bromocriptine is classified as pregnancy‑category B (no proven fetal risk in animal studies). If surgery is postponed, a low dose can be continued under specialist supervision, but the drug is typically switched to a somatostatin analogue after the first trimester.
Older adults (>70years) may be more sensitive to hypotensive episodes. Starting at 1.25mg daily and titrating slowly, while checking orthostatic vitals, minimizes falls.
In resource‑limited settings where injectable drugs are scarce, bromocriptine’s low price (≈AU$20 per month) makes it the backbone of acromegaly care. Coordinating with local pharmacies for consistent supply is essential to avoid treatment interruptions that could cause rebound GH spikes.
Where to Go Next
If you’ve just started bromocriptine, the next step is to schedule a baseline IGF‑1 test and a pituitary MRI if you haven’t had one in the past six months. Talk to your endocrinologist about a clear titration plan and ask for a written side‑effect diary.
For readers wanting deeper insight, the logical follow‑up topics are:
- ‘Somatostatin Analogues vs Dopamine Agonists: Choosing the Right First‑Line Drug’
- ‘Pegvisomant: When to Use a GH‑Receptor Blocker’
- ‘Surgical Techniques for Pituitary Adenomas and Their Success Rates’
These articles sit in the same knowledge hierarchy, moving from medication‑specific overviews to broader treatment algorithms.
Frequently Asked Questions
How long does it take for bromocriptine to lower IGF‑1?
Most patients see a measurable drop in IGF‑1 within 4-6weeks of reaching a stable dose. Full normalisation, if it occurs, usually requires 3-6months of consistent therapy.
Can bromocriptine be combined with other drugs?
Yes. Adding a somatostatin analogue or pegvisomant can boost IGF‑1 control in patients who don’t respond fully to bromocriptine alone. Combination therapy is common in resistant cases, but doctors monitor for additive side‑effects.
What should I do if I feel dizzy after taking bromocriptine?
Dizziness often stems from orthostatic hypotension. Try taking the dose with food, split the total daily amount into smaller doses, and rise slowly from sitting or lying positions. If symptoms persist, contact your endocrinologist for a possible dose reduction.
Is bromocriptine safe for long‑term use?
Long‑term data spanning over two decades show bromocriptine is generally safe when monitored. The main concerns are chronic nausea and rare cardiac valve changes; periodic cardiac reviews and liver function tests mitigate these risks.
How does bromocriptine compare cost‑wise to other treatments?
A monthly supply of bromocriptine costs around AU$20-30 in Australia, far cheaper than octreotide (≈AU$800 per month) or pegvisomant (≈AU$2,500 per month). This price difference makes it the go‑to option where budgets are tight.
Will bromocriptine shrink my pituitary tumor?
Tumour shrinkage occurs in a minority (≈15%) of patients, usually after a year of therapy. The primary goal of bromocriptine is hormonal control, not tumour reduction; surgery remains the most reliable way to achieve size decrease.
Can I stop bromocriptine once my IGF‑1 is normal?
Abrupt discontinuation is discouraged. Hormone levels can rebound quickly, so tapering under medical supervision is required. Some clinicians maintain a low maintenance dose indefinitely to keep the disease quiescent.