Antagonism by domperidone of the ocular hypotensive effect of pergolide

1. The effect of pre-dosing with 15 mg domperidone, a relatively selective dopamine 2-receptor antagonist, on the ocular hypotensive action of a single oral dose of 25 micrograms pergolide, a dopamine 2-receptor agonist, was studied in 9 normal human volunteers, using a non-invasive method. 2. Compared with domperidone followed after 1 h by placebo, placebo followed after 1 h by pergolide had an ocular hypotensive effect in both eyes. Domperidone followed after 1 h by pergolide had no effect on intraocular pressure in both eyes. 3. The results of this study showed that domperidone inhibited the ocular hypotensive action of pergolide, suggesting that pergolide reduces intraocular pressure by the stimulation of the peripheral dopamine 2-receptors.