anti-emetics Flashcards
What are the 3 types of anti-emetics?
H1 receptor antagonists, D2 receptor antagonists and 5-HT3 receptor antagonists.
what is the MOA for h1 receptor antagonists?
inhibit histamine 1 receptors in the vestibular nuclei. Specifically targets motion sickness/morning sickness.
what are the contraindications, side effects and patient/carer advice for cyclizine (h1 receptor antagonists)
contraindication: acute porphyrias and neonate (due to specific antimuscarinic activity in neonates). Side effects= drowsiness/ sedation/ Patient/ carer advice= driving + skilled tasks from sedation. effects of alcohol enhance.
what are the contraindications of promethazine hydrochloride? (hI receptor antagonists)
shouldnt be given to children under 2 year as the safety hasnt been established.
what are the names of H1 receptor antagonists?
cyclizine and promethazone hydrochloride
What are the names of 5-HT3 receptor antagonists?
ondansetron and granisteron
what is the MAO of the 5-HT3 receptor antagonists?
inhibit sub receptor 5-HT3 in the chemoreceptor trigger zone and possibly the GI tract. Good for chemotherapy , can act directly in the gut as theres 5-ht2 receptors there.
discuss ondansteron ( 5-HT3 receptor antagonists)
for post-operative n&v and chemo and radiotherapy. Specific 5-HT3 receptor antagonist which blocks receptors in GI tract/ CNS. Contraindicated in a prolonged QT interval. Side effects: constipation, flushing, headache, injection site reactions. Patient/ carer advice: how to administer orodispensible tablets.
Discuss Granisteron: 5-HT3 receptor antagonists
indication: N&V induced by cytotoxic chemo. 3-5 days where oral anti-emetics may not be used. Patient/carer advice: with transdermal use; should be advised not to expose the patch to sunlight during use and for 10 days after removal.
What is the MOA of D2 receptor antagonists?
inhibit D2 receptors in the chemoreceptor trigger zone.
what are the names of the D2 receptor antagonists?
1) azines (prochloroperazine and chloropromazine), 2) metachlopromine and 3) droperidol
discuss Droperidol: D2 receptor antagonists
for the prevention and treatment of post-operative nausea and vomiting. It is a butyrophenone- structurally related to halperidol- blocks receptors in the CTZ.
Contraindication: bradycardia, CNS depression, comatose states, hypokalamia; prolonged QT interval.
Monitoring requirements: prolactin concentration at start, , 6 months then yearly. Patients with schizophrenia must have physical health monitoring yearly. Continuous pulse oximetry require if at risk of ventricular arrhythmia- continue for 30 mins after administration.
Discuss metoclopromide: D2 receptor antagonists
indication: symptomatic treatment of N&V; migraine; chemo+radiotherapy. Contraindicated 2-4 days after GI surgery; GI haemorrhage; GI obstruction.
MOA: d2 receptor antagonism and agonist on 5-HT receptors.
Side effects: extrapyramidal effects in children and young adults (menstrual changes). Patient/carer advice: counselling on the use of peptide and oral solution.
Discuss prochlorperazine: D2 receptor antagonists
indication: acute attack in N&V.
Contraindication: avoid oral route in children under 10kg and not for children in psychosis.
MOA: block d2 receptors in the CTZ.
Monitoring requirements: adults- prolactin concentrations and physical health. Children: endocrine function- height and weight. Assess sexual maturation and menstral function. Patient/ carer advice: how to administer buccal tablets, photosensitisation, affects skilled tasks.
