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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Prolactinoma and hyperprolactinaemia

Endocrinology and metabolism · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull

Synopsis

Confirm biologically relevant prolactin excess, distinguish medicine, pregnancy, systemic and stalk causes from prolactinoma, and deliver safe dopamine-agonist, visual, fertility and pregnancy care.

  • Hyperprolactinaemia suppresses pulsatile GnRH, reducing LH and FSH and causing amenorrhoea, anovulation, infertility, low libido, erectile dysfunction and bone loss; galactorrhoea is neither necessary nor specific.
  • Before calling a pituitary tumour, exclude pregnancy, primary hypothyroidism, renal or hepatic disease, chest-wall stimulation and medicines such as antipsychotics, metoclopramide, domperidone, opioids and some antidepressants.
  • Repeat a modest prolactin under calm sampling conditions and ask the laboratory about macroprolactin when symptoms and result disagree; venepuncture stress can raise the concentration.
A large sellar lesion with only modest prolactin requires assay dilution to exclude the hook effect, while stalk compression usually causes a lesser elevation through lost dopamine inhibition.
  • Dedicated pituitary MRI, formal fields when the chiasm is threatened and the full pituitary profile complete classification; image only after obvious physiological and medicine explanations are assessed appropriately.
  • Cabergoline is first-line for most prolactinomas because it lowers hormone and shrinks tumour; a visually compressive macroprolactinoma often improves medically but needs close early objective review.
  • Dopamine agonists can restore ovulation before menstruation returns, so contraception or planned conception advice must accompany the first prescription.
  • Transsphenoidal surgery is considered for intolerance, true resistance, selected cystic or compressive disease, CSF leak or patient preference in an experienced pituitary centre.

    • Key red flags

    Acute severe headache, visual loss, ophthalmoplegia or reduced consciousness suggests pituitary apoplexy and requires emergency cortisol and neurosurgical management.

    Rapidly progressive visual field or acuity deficit from a macroadenoma needs same-day pituitary review and cannot wait for slow outpatient dose titration.

    A large lesion with low cortisol, hypotension, vomiting, hyponatraemia or hypoglycaemia may have ACTH deficiency requiring immediate glucocorticoid protection.

    Clear rhinorrhoea developing after rapid dopamine-agonist tumour shrinkage can represent CSF leak and needs urgent skull-base assessment because of meningitis risk.

    Severe headache or new visual symptoms during pregnancy in a patient with macroprolactinoma requires urgent endocrine, obstetric and neuro-ophthalmic evaluation.

    Investigation priorities

    01
    Repeat serum prolactinFirst step

    Confirm persistence and judge the magnitude under conditions that minimise transient stress elevation.

    Management branches

    CONFIRMRaised prolactin result

    A laboratory concentration is above the reference range without an established prolactinoma.

    1. Check pregnancy, symptoms, stress, breast or chest stimulation, thyroid, renal and hepatic function and every relevant prescription or recreational drug.
    2. Repeat modest elevations and request macroprolactin evaluation when biology and concentration do not align.
    3. If a large lesion or mass symptoms are present, obtain diluted prolactin urgently to exclude the hook effect and assess all pituitary axes.
    4. Arrange dedicated MRI and specialist referral when persistent monomeric elevation, significant symptoms or tumour concern remains.

    Key medicines

    CabergolineThe current SmPC starts hyperprolactinaemia treatment at 0.5 mg weekly in one or two doses, with gradual specialist titration to response.Give with food and review postural hypotension, nausea, somnolence, impulse-control or psychiatric effects; use baseline and follow-up cardiac-fibrosis assessment according to SmPC and local policy.
    BromocriptineUse a low starting dose with food and increase slowly under the current BNF regimen when cabergoline is unsuitable or a pregnancy pathway favours it.Nausea, postural hypotension, headache, sleepiness and psychiatric effects can limit adherence; check interactions and avoid abrupt unsupervised changes around pregnancy.
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    Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
    Sources

    Sources and review status

    National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

    • Cabergoline UK SmPCCurrent indication, dose, fertility, pregnancy, impulse-control and fibrotic safety.
    • NICE BNF CabergolineCurrent British prescribing and interaction reference.
    • NICE NG257 Fertility problemsCurrent 2026 UK fertility treatment context for hyperprolactinaemic ovulatory disorder.
    • NNUH pituitary tumour emergency guidelineNHS hook-effect, visual-field and urgent macroadenoma pathway.
    • University Hospitals Sussex cabergoline treatmentCurrent NHS patient-facing implementation for prolactinoma shrinkage and follow-up.

    Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

    Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom