Impulse control disorders

Patients and their carers should be informed about the risk of impulse control disorders (including pathological gambling, binge eating, and hypersexuality) associated with dopamine-receptor agonists. There is no evidence that ergot- and non-ergot-derived dopamine-receptor agonists differ in their propensity to cause impulse control disorders, so switching between dopamine-receptor agonists to control these side-effects is not recommended.

If the patient develops an impulse control disorder, the dopamine-receptor agonist should be withdrawn or the dose reduced until the symptoms resolve.

Fibrotic reactions

Ergot-derived dopamine-receptor agonists, bromocriptine, cabergoline, and pergolide, have been associated with pulmonary, retroperitoneal, and pericardial fibrotic reactions.

Exclude cardiac valvulopathy with echocardiography before starting treatment with these ergot derivatives for Parkinson's disease or chronic endocrine disorders (excludes suppression of lactation); it may also be appropriate to measure the erythrocyte sedimentation rate and serum creatinine and to obtain a chest X-ray. Patients should be monitored for dyspnoea, persistent cough, chest pain, cardiac failure, and abdominal pain or tenderness. If long-term treatment is expected, then lung-function tests may also be helpful.

Patients taking cabergoline should be regularly monitored for cardiac fibrosis by echocardiography (within 3–6 months of initiating treatment and subsequently at 6–12 month intervals).

Refer to MHRA Drug Safety Update (October 2008), and individual summary of product characteristics for further details regarding fibrotic reactions.

Cabergoline

• Tablets 500 micrograms, 1mg, 2mg (£13.74 = 1mg weekly)

Indications and dose

• Hyperprolactinaemic disorders
  • Initially 250–500 micrograms weekly (as a single dose or as 2 divided doses on separate days); increased in steps of 500 micrograms every month until optimal therapeutic response reached; increase dose following monitoring of serum prolactin levels; usual dose 1mg weekly (range 0.25–2 mg once weekly); usual maximum 4.5 mg per week
  • Doses over 1 mg weekly to be given as divided doses, and doses should not exceed 3mg per day
  • Reduce initial dose and increase more gradually if patient intolerant

Notes

1. Exclude pregnancy before administration of cabergoline; women who are planning pregnancy should stop taking cabergoline 1 month before they try to conceive
2. See notes above regarding impulse control disorders and fibrotic reactions
3. There can be variation in the licensing of different medicines containing the same drug. (refer to individual product SPC)
4. Annual costs can vary greatly depending on required dose, and strength of tablet used; please prescribe prudently to ensure efficient use of NHS resources

Bromocriptine

• Tablets 2.5mg (£74.99 = 30 x 2.5mg)

Indications and dose

• Acromegaly; prolactinoma
  • Initially 1–1.25 mg daily, dose to be taken at bedtime, then increased gradually to 5 mg every 6 hours
• Galactorrhoea
  • Initially 1–1.25 mg daily, dose to be taken at bedtime, increase dose gradually; usual dose 7.5 mg daily in divided doses, increased if necessary up to 30 mg daily
• Prevention of lactation
  • Initially 2.5 mg daily for 1 day, then 2.5 mg twice daily for 14 days.
• Suppression of lactation
  • Initially 2.5 mg daily for 2–3 days, then 2.5 mg twice daily for 14 days

Notes

1. See notes above regarding impulse control disorders and fibrotic reactions
2. There can be variation in the licensing of different medicines containing the same drug. (refer to individual product SPC)
3. Annual costs can vary greatly depending on required dose, and strength of tablet/capsule used; please prescribe prudently to ensure efficient use of NHS resources