Drug-induced hyperprolactinaemia

The main drugs which induce hyperprolactinaemia are:

• major tranquilisers - block dopamine binding sites
• metoclopramide - block dopamine binding sites
• tricyclic antidepressants - block catecholamine re-uptake
• reserpine - depletes catecholamines
• methyldopa - blocks conversion of tyrosine to dihydroxyphenylalanine and dopamine
• oral contraceptives - promote the synthesis and storage of prolactin
• bendrofluazide, omeprazole, ranitidine, cimetidine and famotidine have occasionally been reported to cause hyperprolactinaemia

Drug-induced increases in serum prolactin do not generally lead to levels above 2500 mU/L; however occasionally levels up to 6000 mU/L have been observed (1).

In cases of suspected drug-induced hyperprolactinaemia where very high levels of prolactin are seen (over 2500 mU/L) then detailed physical examination (including visual fields), pituitary imaging and measurement of pituitary hormone levels are indicated.

Reference:

1. Soto-Pedre E, Newey PJ, Bevan JS, Greig N, Leese GP. The epidemiology of hyperprolactinaemia over 20 years in the Tayside region of Scotland: the Prolactin Epidemiology, Audit and Research Study (PROLEARS). Clin Endocrinol (Oxf). 2017 Jan;86 (1):60–7