Palliative Drugs Flashcards
Name two dopaminergic antiemetics
Domperidone
Metclopramide
When are anti-dopaminergic antiemetics indicated
N+V due to reduced gut motility
Where are D2 receptors found
Chemoreceptor trigger zone
What is role of domperidone and metclopramide
D2 receptor antagonists
What is role of D2 in the gut
Causes relaxation of LOS and gut
What is the role of D2 receptor antagonists
Increase peristaltic contraction
What is a gastric side effect of anti-dopaminergic anti-emetics
Diarrhoea
What can metclopramide cause
Extrapyramidal side effects - usually in the form of acute dystonic reaction
What is acute dystonia
Sustained muscle contraction
Name two types of acute dystonic reaction
- Torticolis
- Oculogyric crisis
What is an oculogyric crisis
Sustained upward deviation of the eyes
Why does domperidone not cause extra-pyramidal SEs
- As it does not cross the BBB
What is a specific side effect of domperidone
- Prolongs the QT interval predisposing to arrhythmias
What is done to reduce risk of extrapyramidal SEs with metlcoptramide
- Prescribe for less than 5 days
What are two absolute CIs of metclopramide and domperidone
- Neonates (Increase adverse effects)
- Intestinal obstruction and perforation
What is an absolute CI of domperidone
Prolong QT Syndrome
When should metclopramide be avoided
Parkinson’s Disease
What drug should metclopramide not be combined with
Dopaminergic agents for PD - as antagonist each other
What drugs should domperidone not be prescribed with
- Other drugs prolong QT (SSRI, Macrolide)
- CYP450 Inhibitors
What increases risk of extra-pyramidal SEs
prescribing with an antipsychotic
Name 3 anti-histamine anti-emetics
Cylizine
Promethazine
Cinnarizine
When are anti-histamine anti-emetics useful
- Motion sickness
- Nausea due to vestibular problems
Where are H1 and muscarinic receptors located in nausea
Vomiting centres
What is the main side effect of H1 antagonism
Drowsiness
