Bromocriptine for visual field defects in prolactinomas.

The introduction of bromocriptine (2-brocergocryptine mesylate), a semi-synthetic ergot alkaloid, has revolutionised the treatment of the amenorrhoeagalactorrhoea syndrome due to excessive prolactin secretion (Thorner et. al., 1975). In a significant number of cases, this hyperprolactinaemia is caused by a radiologically obvious pituitary tumour (L'Hermite et. al., 1977; Bergh et al., 1978 a) which may expand causing pressure effects on adjacent structures notably the optic chiasma. Optic chiasmal compression resulting in visual field impairments may occur in nonpregnant patients with radiologically normal fossae (Vaidya et. al., 1978) but is more common during pregnancy especially when a large tumour is present (Corenblum et al, 1975; Bergh et al, 1978 b; Burzaco et al, 1978). Many authors would therefore recommend that hyperprolactinaemic patients with even the slightest suggestion of fossa enlargement should not be allowed to become pregnant until definitive treatment is instituted to the adenoma either by irradiation or a surgical removal (Hardy, 1973; Child et al,1975; Besser, 1978). Prolactin secretion is under an inhibitory control by the hypothalamus through the prolactin