Antiemetics Flashcards
Metroclopramide
Action: dopamine receptor antagonist.
Increases gastric emptying.
Side effect: movement disorder
How do antiemetic a work?
The vomiting centre in the brainstem and the associated chemoreceptors trigger zone (CTZ) in the fourth ventricle may be stimulated by different chemical and neurotransmitters well as certain drugs.
Drugs that prevent vomiting work in many different ways.
Prochlorperazine Domperidone
Dopamine receptor antagonist
Side effects: drowsiness. Movement disorder.
Hyoscine
Acetylcholine receptor antagonist. Action on vestibular apparatus in inner ear.
Side efforts: dry mouth and blurred visio. Reduces gastric motility.
Ondansetron
5-HT receptor antagonist
Side effect- flushing and hiccups
Cyclizine
Antihistamine
Side effect : drowsiness
Dexamethasone
Steroid. Reduces inflammatory mediators.
Side effects: those of steroids.
What drug is effective for vomiting due to chemotherapy with low risk if vomiting - prevention
Phenothiazine e.g. Prochlorperazine - May cause drowsiness. Domperidone may be used - less drowsiness. Continue for 24 hrs after treatment finishes.
Drug for chemotherapy drugs with a higher risk of vomiting…
Add corticosteroid e.g. Dexamethasone alone or with a benzodiazepine e.g lorazepam, prior to commencing therapy.
Chemotherapy drugs with high risk - best drug…
5-HT3, antagonist e.g ondansetrin. Usually effective.
Post surgery vomiting. Best drug…
Metoclopramide or Prochlorperazine. Ondansetron or antihistamine such as cyclizine.
Vomiting associated with GI tract, biliary or hepatic disease. Best drug…
Metroclopramide may be more effective.
Vomiting due to opioids. Drugs …
Prochlorperazine, metroclopramide, cyclizine.
Migraine. Best antiemetic …
Metroclopramide, Domperidone, phenothiazines or antihistamines may be used
Motion sickness. Best drug…
Hyoscine - transdermal patch applied a few hours before journey
Cyclizine or cinnarizine - are also effective and may be better tolerate but caused drowsiness.
