Anti emetic Flashcards
GI vomiting que
Toxins/poisons induce 5-HT release from enterochromaffin cells which triple the vagal afferent fibres
CNS vomiting que
The medulla has the vomiting centre, triggered by the chemoreceptor trigger zone (CTZ)
Acute vomiting que
triggered by 5HT and the 5HT3 receptor in stomach (0-24h)
Delayed vomiting que
triggered by substance P and Neurokinin 1 signalling the CTZ
Ondansetron
5-HT3 antagonist
-Primarily act in CTZ to prevent vomiting
-some action in stomach
—–
-treats and prevents motion sickness
-chemo induced vomiting
—-
-slows GI transit
Otherwise well tolerated
5-HT3 receptor
qFound in CTZ and stomach
-sensitize spine neurons and induce vagal nausea signal
-also act on vagal afferent fibres to medulla
-also stimulates intestinal transit
Granisetron
5-HT3 antagonist
-Primarily act in CTZ to prevent vomiting
-some action in stomach
—–
-treats and prevents motion sickness
-chemo induced vomiting
—-
-slows GI transit
Otherwise well tolerated
Alosetron
5-HT3 antagonist
-Primarily act in CTZ to prevent vomiting
-some action in stomach
—–
-treats and prevents motion sickness
-chemo induced vomiting
—-
-ishcemic colitis
-slows GI transit
Otherwise well tolerated
Palonosetron
5-HT3 antagonist
-Primarily act in CTZ to prevent vomiting
-some action in stomach
—–
-treats and prevents motion sickness
-chemo induced vomiting
—-
-slows GI transit
Otherwise well tolerated
D2 receptor (emetics)
Effects mainly D2 (Gq linked) activates PLC increasing IP3 thus Ca+ and DAG. decreasing neuron excitability
Chlorpromazine
D2 antagonist (Phenothiazine)
-Lowers neuron excitability in CTZ
—
-cancer, radiation, cytotoxic, opioid and anaesthetic induced vomiting
—
-extrapyramidal syndrome (parkinson)
-dystonias
-tardive dyskinesia
-hyperprolactinemia
Perphenazine
D2 antagonist (Phenothiazine)
-Lowers neuron excitability in CTZ
—
-cancer, radiation, cytotoxic, opioid and anaesthetic induced vomiting
—
-extrapyramidal syndrome (parkinson)
-dystonias
-tardive dyskinesia
-hyperprolactinemia
Prochlorperazine
D2 antagonist (Phenothiazine)
-Lowers neuron excitability in CTZ
—
-cancer, radiation, cytotoxic, opioid and anaesthetic induced vomiting
—
-extrapyramidal syndrome (parkinson)
-dystonias
-tardive dyskinesia
-hyperprolactinemia
Trifluoperazine
D2 antagonist (Phenothiazine)
-Lowers neuron excitability in CTZ
—
-cancer, radiation, cytotoxic, opioid and anaesthetic induced vomiting
—
-extrapyramidal syndrome (parkinson)
-dystonias
-tardive dyskinesia
-hyperprolactinemia
Metoclopramide
D2 antagonist (Phenothiazine), histamine and AChR antagonist
-Lowers neuron excitability in CTZ
-only increases transit in esophagus
-CNS D2 block
—
-cancer, radiation, cytotoxic, opioid and anaesthetic induced vomiting
—
-spasmodic torticollis(neck contractions)
-occulogyric crises (eye movemtns)
-hyperprolactinemia
