Hyperprolactinaemia

Causes of hyperprolactinaemia:

Physiological:

• Sleep (REM phase)
• Pregnancy
• Suckling
• Stress
• Coitus

Pathological:

• Neoplasm
• PCOS
• Primary hypothyroidism
• Renal failure
• Liver failure
• Idiopathic

Drug-induced:

• Dopamine antagonists (e.g. metoclopramide and phenothiazines)
• Oestrogens
• Opiates
• Cimetidine (H₂-receptor antagonist)
• Methyldopa (α₂-adrenoceptor agonist)

Clinical features:

• Galactorrhoea
• Oligomenorrhoea/amenorrhoea
• Decreased libido in both sexes
• Decreased potency in men
• Subfertility
• Symptoms and signs of oestrogen or androgen deficiency (in the long-term, osteoporosis may result, especially in women)

Investigations:

At least 3 prolactin levels should be measured. The following tests are appropriate after physiological and drug causes have been excluded:

• Visual fields should be checked
• Anterior pituitary function should be assessed
• MRI of the pituitary

Treatment:

Drugs:

• Hyperprolactinaemia should be reduced with a dopamine agonist

• Bromocriptine is the best established therapy
• Initial doses should be small (e.g. 1mg) and taken with food, or at bedtime
• The dose should be gradually increased, usually to 2.5mg BID or TID, judged on clinical response and prolactin levels

Trans-sphenoidal surgery:

• Only really successful in patients with a microadenoma (not macroadenoma)

Radiotherapy:

• Slowly effective
• Can sometimes cause eventual hypopituitarism