metoclopramide Flashcards
What is metoclopramide?
dopamine D2 antagonist used as an antiemetic (effective against nausea and vomiting)
What class of drugs does metoclopramide belong to?
antiemtics/antinauseants
dopamine antagonists
prokinetic agents
What are other drugs in the same class as metoclopramide?
prochlorperazine maleate promethazine theoclate hyoscine hydrobromide droperidol domperidone cyclizine hydrochloride ondanestron
What is the mechanism of action of metoclopramide?
Stimulates motility of upper GIT without stimulating gastric, biliary or pancreatic secretions. via increasing resting pressure of lower oesophageal sphincter.
Improves acid clearance from oesophagus by increasing amplitude of oesophageal peristaltic contractions.
Sensitises tissues to ACh and increases cholinergic response to GI smooth muscle.
Accelerates intestinal transit and gastric emptying by preventing relaxation of gastric body and increasing the phasic activity of the antrum. There is also simultaneous relaxation of upper SI resulting in improved coordination between body, antrum and the upper SI.
What is the relevant pharmacokinetic/pharmacodynamic properties of metoclopramide?
rapidly absorbed with oral bioavailability ~80% Volume of distribution 4.4L/Kg 30% protein binding hepatically metabolised 85% eliminated by urine Half life of 5-6 hours
What is metoclopramide indicated for?
nausea and vomiting
gastro intestinal prokinetic (e.g. in funtional dyspepsia, GORD, post operative gastro-duodenal dysfunction)
also used in nausea and vomiting due to chemotherapy or radiotherapy
What is the role of therapy of metoclopramide in GORD?
2nd line agent (?) used to increase gastric emptying and increase the LOS pressure
What is the dose of Metoclopramide used in GORD, dyspepsia and other GI disorders?
Oral: 10mg tds (adult)
What are the precautions associated with metoclopramide use?
Elderly, young adults (15-19 years), children.
atopic allergy (incl. asthma)
cardiac conduction disturbances (incl. concomitant use of other drugs affecting cardiac conduction)
Use of metoclopramide may mask underlying disorders like cerebral irritation, epilepsy, parkinson’s, history of depression, hypertension
What are the contraindications with metoclopramide use?
GI obstruction, perforation or haemorrhage
3-4days after GI surgery
concomitant drugs that may cause extrapyramidal adverse effects (various movement disorders such as acute dystonic reactions, pseudoparkinoism, tardive dyskinesia or akathisia)
and pheochromocytoma which is a neuroendocrine tumor of the medulla of adrenal glands.
What are the adverse effects with metoclopramide use?
extrapyramidal effects (esp. in children and young adults) drowsiness, restlessness,
Less common: bowel disturbances, insomnia, headache, dizziness, delirium, obsessive rumination, mania ,
rarely: depression
What are the interactions associated with metoclopramide use?
Increases plasma concentration of ciclosporin
Possible Increased absoprtion of alcohol
increased risk of side effects when given with antipsychotics
CNS toxicity with SSRIs
Antagonised GI activity when given with antimuscarinics, opiod analgesics
Increases rate of absorption of aspirin, paracetamol
What are the warning bells associated with metoclopramide use?
be aware of extrapyramidal effects
Should only be used in adults over 18 years for the prevention of postoperative nausea and vomiting, radiotherapy induced nausea and vomiting, delayed (not acute) chemo induced nausea and vomiting.
Should only be used short term (5 days)
Maximum dose is 500ug/kg
What monitoring is involved in metoclopramide use?
look for tradive dyskinesia. (fine vermicular movements of the tongue is an early symptoms)
