Metoclopramide

Metoclopramide is a dopamine antagonist with prokinetic and antiemetic properties, prescribed for the short-term management of nausea and vomiting, including that associated with acute migraine, post-operative states, radiotherapy, and chemotherapy.

It is also used to relieve symptoms of gastroparesis and delayed gastric emptying.

Metoclopramide exerts its antiemetic effect by blocking dopamine D2 receptors in the chemoreceptor trigger zone of the brain.

Its prokinetic action on the upper gastrointestinal tract increases gastric motility, accelerates gastric emptying, and strengthens the tone of the lower oesophageal sphincter.

At higher doses, it also has some antagonistic activity at 5-HT3 receptors, contributing additional antiemetic efficacy.

Following a European regulatory review, the use of metoclopramide has been restricted to short-term treatment (up to five days) at reduced maximum doses, owing to the risk of neurological side effects including extrapyramidal reactions and tardive dyskinesia.

It remains a valuable antiemetic when used appropriately within these guidelines.

Take metoclopramide 30 minutes before meals or at the onset of nausea. Swallow tablets whole with a glass of water. Treatment should be limited to a maximum of five days.

Do not exceed the recommended dose or duration of treatment. If symptoms persist beyond five days, seek further medical advice.

Metoclopramide is also available as an injection for hospital use when oral administration is not possible.

Adults aged 18 years and over: 10 mg up to three times daily. The maximum recommended dose in 24 hours is 30 mg or 0.5 mg/kg body weight, whichever is lower.

Treatment duration must not exceed five days. Metoclopramide is not recommended for children under 18 years for most indications due to the higher risk of extrapyramidal reactions.

In patients with renal impairment, reduce the dose by 50% in moderate impairment and by 75% in severe impairment.

Common (1 in 10 to 1 in 100): drowsiness, fatigue, restlessness, diarrhoea, asthenia.

Uncommon (1 in 100 to 1 in 1,000): extrapyramidal reactions (acute dystonia, akathisia, Parkinsonism), depression, hypotension, galactorrhoea, amenorrhoea.

Rare (1 in 1,000 to 1 in 10,000): tardive dyskinesia (more likely with prolonged use), neuroleptic malignant syndrome, methaemoglobinaemia, cardiac conduction disorders.

Extrapyramidal reactions are more common in children and young adults and usually resolve upon discontinuation.

Do not use metoclopramide for more than five days. The risk of tardive dyskinesia increases with duration and total cumulative dose.

Extrapyramidal reactions may occur, particularly in young adults and children; discontinue immediately if involuntary movements develop.

Metoclopramide should be used with caution in patients with Parkinson's disease, epilepsy, or phaeochromocytoma. Avoid concurrent use with other dopamine antagonists.

It may impair the ability to drive or operate machinery.

Metoclopramide is contraindicated in patients with gastrointestinal haemorrhage, mechanical bowel obstruction or perforation, phaeochromocytoma (confirmed or suspected), history of tardive dyskinesia caused by neuroleptics or metoclopramide, epilepsy, and hypersensitivity to metoclopramide.

It must not be used concurrently with levodopa or dopamine agonists. It is not recommended in children under 1 year of age.