MOTILIUM® tablets COMPOSITION Each tablet contains 10 mg domperidone. PHARMACOLOGICAL CLASSIFICATION A.5.7.2 Anti-emetics and anti-vertigo preparations. PHARMACOLOGICAL ACTION Domperidone is a dopamine-receptor blocking agent. Its action on the dopamine-receptors in the chemo-emetic trigger zone produces an anti-emetic effect. Domperidone does not cross the blood-brain barrier to any appreciable degree and so exerts relatively little effect on cerebral dopaminergic receptors. Domperidone has been shown to increase the duration of antral and duodenal contractions to increase gastric emptying. Domperidone does not alter gastric secretions and has no effect on intracranial pressure or on the cardiovascular system. Domperidone is rapidly absorbed, with peak plasma concentrations at approximately 1 hour after oral administration. The absolute bio-availability of oral domperidone is low (approximately 15%) due to first-pass hepatic and intestinal metabolism. Domperidone is 91 to 93% bound to plasma proteins. The plasma half-life after a single oral dose is 7 to 9 hours in healthy subjects but is prolonged in patients with severe renal insufficiency. Domperidone undergoes rapid and extensive hepatic metabolism by hydroxylation and N-dealkylation. In vitro metabolism experiments with diagnostic inhibitors revealed that CYP3A4 is a major form of cytochrome P-450 involved in the N-dealkylation of domperidone, whereas CYP3A4, CYP1A2 and CYP2E1 are involved in domperidone aromatic hydroxylation. Urinary and faecal excretion amount to 31% and 66% of the oral dose, respectively. The proportion of drug excreted unchanged is small (approximately 1% of urinary and 10% of faecal excretion). INDICATIONS MOTILIUM is indicated for:- Delayed gastric emptying of functional origin with gastro-oesophageal reflux and/or dyspepsia. - Control of nausea and vomiting of central or local origin. - As an anti-emetic in patients receiving cytostatic and radiation therapy. - Facilitates radiological examination of the upper gastro-intestinal tract. CONTRA-INDICATIONS MOTILIUM is contra-indicated in patients with known hypersensitivity to domperidone. MOTILIUM should not be used whenever stimulation of gastric motility is to be avoided or could be harmful, eg. in the presence of gastro-intestinal haemorrhage, obstruction or perforation. MOTILIUM is also contra-indicated in patients with a prolactin-releasing pituitary tumour (prolactinoma). The safety of use during pregnancy and lactation has not been established.